I was kind of worried about this down the road with mine. When I swapped out the frame, I punched my vin into the replacement frame. I am sure it was probably not the "right" thing to do, but if it ever gets checked, the numbers will match. I am not sure how anyone would really verify the frame vin here in the rust belt, anyway. The only way to make them close to legible is to sandblast or wire wheel all the rust scale and grime away.