I got a GT last week and I am not 100% positive what model it is. I beleive it is a 88 Mach 1 but if anyone can tell me for sure from the serial number I would greatly appreciate it. The serial number is 12880679 and next to it a little down is M1. The rar triangle tubes start before the seat tube instead of after it.
Thanks Guys...Scott

the "1288" in the serial is the month/year it was made and the "M1" is indeed mach 1. being that it was built in december of '88 it is probably a 1989 year model. i forget if there was any physical difference between an '88 and '89...they might be the same.

yup, what mr coasterbrake said..
12/88 mach 1 stickered and sold as an 89 (because thats the way its done)

Thanks guys, thats what I thought, but I wanted to be sure..