The 48 thing is weird but I got it figured out.
Speed Demon on the last album is 48 bars, exactly. This new joint is also exactly 48 bars. I'm guessing that the new single was called Another 48 at first, and then they realized people would be confused and wonder where the first 48 was, so they just changed the title to First 48 after the artwork was made...and plus First 48 is a television show so that gives the name a little double meaning.
So yeah. First 48 Freestyle = Another 48 Freestyle on Bo Jackson...and if you want to go listen to the original 48 bars from Boldy, then Speed Demon Freestyle on Tea in China has it for you.
All make sense.