No.
The attempt on Reagan by John Hinckley, Jr. in March of 1981, which you can read a little bit about by
/u/jbdyer here was essentially irrelevant when the election took place over 3 1/2 years later.
/u/Kochevnik81 points out that there was a brief bit of sympathy bump towards Reagan reflected in his overall approval rating going from 60% to 68%, but that was a drop in the bucket compared to the impact of the 1981-1982 recession, which while not technically starting until July 1981 had already started to gnaw at his honeymoon ratings upon taking office even at the time of the attempt, and went full bore by 1982 where Reagan bottomed out in the 30% range. His later ratings bounced around significantly based primarily on the economy with foreign affairs and Iran-Contra sometimes playing roles, but never the assassination beyond the first month or so.
There's a series of longer answers about Reagan's reelection campaign in the
rest of the thread mentioned above which is worth reading; I would add to it by paraphrasing a quote by the late, great dean of Washington political journalists David Broder that if you could figure out how to provide $1.00 of government for $0.85 using deficit financing as well as convince the people that it was a good thing that you were doing so, you'd be in power for a long time, and the 1984 campaign was at its core the first real test of that.
This bears out with other attempts. In 1975, Squeaky Fromme very nearly got a shot off with a .45 Colt at Gerald Ford from immensely close quarters (two feet away), with only a very quick thinking Secret Service agent, Larry Buendorf, sticking the membrane between his thumb and forefinger under the hammer to prevent the gun from firing and the President from a devastating wound. A little over two weeks later, when Sara Jane Moore fired at him with a .38 from about 40 feet away, it was only that Oliver Sipple, a disabled former Marine having grabbed for the gun at the last moment that made her bungle the shot (which hit a cab driver in the groin, although fortunately he wasn't seriously injured.) Richard Norton Smith dedicated his recent biography of Ford,
An Ordinary Man, to Sipple, as the aftereffects of it ruined his life and are generally unknown; he was unwillingly outed by the
San Francisco Chronicle as gay, which in 1975 got him disowned by his Michigan parents, and lived a pretty miserable life in a shoddy apartment in a bad neighborhood until he was found dead in 1989 after likely having his body sit there for two weeks prior. In it, the framed thank you letter from Ford - which was all he ever did for the man who'd saved his life - was given a place of honor among the news stories about the attempt.
But Ford got very little if any boost from the attempt, and by 1976 it was not mentioned in the campaign; Ford's gaffe over Poland and Carter's several gaffes were what moved the needle. Nor have I ever seen it suggested in the lit that Roosevelt being targeted by Zangara in 1933 when the latter aimed at him and killed Anton Cermak instead or Truman at Blair House with the Puerto Rican nationalists in 1947 (where he may have initially been looking out the window at was going on - this is a bit unclear, but the Secret Service's reaction getting him the hell out of there wasn't) had any effect whatsoever on their next election.
The only time that I'm aware of (and there are plentiful other assassination attempts in the 19th and even early 20th century that were never written about in the press at the time because there was a general policy by multiple administrations to avoid giving motivation to future 'cranks'; you can see a little about White House security
here and Ayton's
Plotting to Kill The President goes through them more thoroughly) that a significant attempt occurred during a campaign was with Teddy Roosevelt on October 14, 1912 by John Schrank in Milwaukee. The bullet was slowed by the 50 page speech in his pocket and ended up in his chest muscle (where it remained for the rest of his life), TR realized he wasn't seriously wounded by not spitting up blood from a pulmonary injury, gave one of the all time great campaign zingers in "it takes more than that to kill a Bull Moose", prevented Schrank from being lynched and had the two members of his staff who subdued him bring him over to face him eye to eye, and turned him over to the police and finished the 50 minute speech with the crowd in stunned silence. Only then, finally, TR allowed himself to be brought to a hospital.
It's noteworthy that Secret Service protection was still not given to candidates or ex-Presidents for many decades to come after this; the former only changes in 1968 with RFK's assassination, and the latter in the early 1960s after JFK's assassination, so it was TR's own personal bodyguard and secretary that went after Schrank.
Both Wilson and Taft suspended their campaigns for a few days after this - off the top of my head I think they both waited until TR campaigned again a week or two later - but while we don't have real polling data for that election, it quickly faded from news headlines and was like the other assassination attempts pretty much irrelevant by the time the 1912 election took place a little under a month later, even though it added to TR's image much the same way Andrew Jackson's had been enhanced in 1835 when Richard Lawrence's two pistols had misfired and Jackson walked away unscathed.
