Any help on finding out year or model for older exmark

Hi i just recently bought my older exmark at a garage sale and need help finding out model, year, and manual for parts.( I think gearbox is bad) Heres what i know about it:
Walk behind mower
has FB460v motor
Its a 48" cut
I looks older and has old style hand levers
no markings (stickers warn off)
Model No. says on tag 48-12.5k-p
serial N0 11290
Made in Beatrice NE

Any help on finding out year or model for older exmark