I need help identifying a redline I just recently aquired!! If anyone can help, I would really appreciate it!! I have a friend who gave me a redline bike, its definitely from the 80's, and is in pretty bad shape, but I feel like I can restore it to its glory!! The serial number is 503725, with redline stamped with the oval stamp on the bottom bracket!! I think it is an MX-2, but before I buy some replacement decals I would like to make sure!! Does anyone know what model Redline this is, could it be a 600a?? Alot of the redline frames look the same, but I do know that this particular model has the small gussett on the back of the seat tube, which I do not think is on all models!! HELP!! If you know which decal set should be bought for this model, please post an answer!! Thanks, Jason

If the head tube is 4" it could be a 600a or 102b. Not a 500a. If it is 5" it could be a PL-20.