There is a difference, but I can't remember what. IIRC the 88s were narrower than the OBS. I thought this would be the other way, but a freind mine wanted to make a 6 lug 14sf for the OBS, and had the whole axle for an 88 14sf 6, and the OBS was couple inchs wider. If I had an older axle I would measure, only have the 88+.