Bo$$ Borden isn't going to go to WWE to do a job as his final match. It wouldn't really make sense. Do a job just to say you've wrestled in WWE? Nah. He's going to want everything mapped out and in writing before signing any type of contract that involves him wrestling a match.
He doesn't need to be a part of WWE but I think he realizes what the fans want and that's at least a HOF induction and a Legends deal so they can release merchandise and put him in video games and whatnot. I'm sure we'll get that once he finally decides he's done with TNA in a few years. As for him wrestling for WWE, I think it's unlikely.