I have a 1991 300trx and a 1992 trx and the wiring is not the same, the speedometer is not located at the same place (moved about 10cm and the 1992 have a cooling fan) other than that i havent noticed any difference, the cdi is in the same place, starter, alternator, charge regulator, handlebars is the same etc. If you call honda i dont think they can tell you if it works , they only see part numbers. My approach would be to try and start it and fix the wiring issues along the way.