Quick update: I just got my hands on an original 1984 Guess bttf vest ( see pics below ) I'm the kid who had the original style bttf Guess jacket new back in 1985-86 when I was 15 & my aunt got ahold of one for me at the Guess outlet in SoCal. If you've read my story, that jacket is long gone & I've been on the hunt for another ever since. This is the closest I've gotten so far. I do own a Max Caddy & have seen several knock off versions, though having owned the original style Guess jacket & now the vest, I can tell you none of the knockoffs can match the feel, nor fit of the original Guess jacket used in the film that were available from 1984-1986 at select Guess outlets. I don't believe these were ever available at Macy's, Imagnim, or Emporium Capwell back in the day as I searched all of those department stores back then & my aunt in Socal told me they had them at the Guess outlet on a clearance rack. I've included a few pics below of my original Guess jacket from 1985-86 ( I'm 15yrs old in that pic ), as well as my Max Caddy jacket with my DeLorean in 2021 ( yes I ended up buying a DMC a few years back with 10k original miles from DMC Florida ), and finally pics of my NEW 1984-86 Guess Vest that is the same pattern minus the sleeves & half trim on the back.
FYI - the picture of me wearing the vest looks a bit washed out in that pic due to the bright lights in front of me, though it's a bit darker in reality, closer to the solo pics I took of the vest. It's in excellent condition for a 39yr old vest.
One last tidbit, on my original Guess jacket from 1985-86 the buttons had a miniature Guess logo ( triangle+guess spelled out) on each button, not to mention the rectangular Guess patch above the left front pocket. I believe my original Guess jacket was a later updated version being manufactured in 1985 as the movie version worn by Michael J Fox, as well as my vest I recently acquired must be an earlier 1984 version when the movie was being filmed as they have no logo whatsoever on the buttons & a triangle Guess patch on the lower left front pocket of the jacket. Also there are no inner pockets in these original Guess jackets, I remember having to put my walkman in the actual front facing pockets, unlike the movie version & knockoff versions which include an inner pocket for your wallet or walkman. Hope this helps others in their efforts to make a better duplicate.