I recently bought my 1st j-body a 1988 pontiac sunbird 2.0 OHC non-turbo.with a 5 speed manual transmission. It's currently being worked on with parts I purchased, but it seems the clutch i supplied is slightly too large?

here's the part i ordered:
https://www.rockauto.com/en/moreinfo.php?pk=8139612&cc=1260830&jsn=402&jsn=402

what other transmission options are/were there for this model year?

Check the Service Parts Identification Label, located on the spare tire well cover for the transmission code. It is probably MR8. That is the Isuzu 5spd. I think that was the only 5spd offered with the 4cyl engine for 88. Your clutch disk should be 8-1/2". The V6 had a 9-1/8", though it wasn't offered in 1988. Maybe a V6 clutch was incorrectly boxed in the one you received.

The clutch disk seems to fit and so does the throwout bearing, it's the drive plate that's the wrong size and different mounting layout. pretty sure the kit i bought is for the turbo models with different trannys. (Getrag?) I believe i've got it figured out. The Luk 04046 kit has the correct diameter drive plate plus it looks identical to the one my mechanic took out.

Strange, the one you linked to is suppose to be for the non-turbo engine. I don't think any of the 4cyl Sunbirds had the Getrag. Quad 4 engines did get a Getrag, but they came along later. They have a different bell housing mount pattern and won't mate to your engine.
Anyway, the Luk clutch kit should be the correct one. They have been around a long time and I'm sure have sold many of their clutches for these cars.

Could be a OHC vs. OHV thing? i really haven't been able to figure it out with just the search function here.but yeah, pretty sure i'm on the right track with the luk kit.