i know these models very well. i've never paid any attention the letter A after the models. i do know for a fact, 1986 was the first year produced this model in the 4x4 version, also..this was honda's very first 4wd model they ever made. 1986 trx350 was dubed the trx350 fourtrax, then in 1987 they came out with the trx350 fourtrax, then in 1988 they had the trx350 fourtrax and trx350D foreman. these ran all the way up until 1989 in u.s.a. then after 1989, canada started selling them as 1990-1993 , which if you were to go to a dealer in canada ( not sure if they still have them at all there ? ), told them you needed a part for a 1990-1993 trx350 fourtrax-foreman ?, they would not find any part for these years, as honda did not produce any model after 1989 in u.s.a, sooo..you had to tell them your 1993 ( does not exsist ) ( really 1989 ) need a such and such part ?, then they could find it..but !!..by now..this part is discontinued..lol.