1986 TRX250 seat

My latest purchase was a 1986 trx250, not the racing one so I guess it would be a utility. Anyway, the PO just redid the seat. Looks like new foam and cover. Problem is the cover does not fit properly. Comparing it to my others, all the same style, different years, the seat foam seems to be thicker. Are the racing seats different than mine? I am wondering if he bought a racing foam instead of the utility. I am not able to find the foam for mine on eBay and I am positive that is where he bought it from. He drilled holes in the plastic and sewed the cover in place. It is starting to rip and I would like to fix it before the cover is destroyed. I was wondering if I can pull the foam out and trim the underside where it touches the plastic. Has anyone run into this before?