The flywheels for the different clutch's are the same, except the later year flywheel is set up for the 9.75" pressure plate (bolt and dowel holes). You could actually machine out an older flywheel to work with the 9.75" PP.
If you take the starter off, if you can see the edge of the PP cover, then it's the 9.75" clutch. The older 9.25" set up used a stamped steel cover, and you can really see it. You'd have to run your finger over the edge of the flywheel to find the edge.
I wouldn't mess with the 9.25" clutch on ebay. It's best left for a museum piece unless you don't mind putting another one in soon after. The 9.25" were way weak for the SHO's engine, and don't hold up long. I bought an '89 last year that still had the 9.25" clutch on it. I lasted 4 days after I took the keys.
The clamping force was weak, and the disc small. The only advantage it had was weight. The stamped PP was light, the later 9.75" PP's are a lot heavier.
If you do end up getting the 9.25" kit off ebay, please weigh it before you install and report the results. I threw away the old 9.25" I had and wanted to weigh it, and never got around to it before I tossed it.
FWIW a newer 9.75" PP on an 8 lb flywheel is probably pretty close in weight (probably a few lbs lighter) compared to the old 9.25" PP on the stock flywheel.
------------------
White 92
SR71SHO - racer '89