If you've had no luck online with the likes on Rock Auto and such, then most fair sized cities will have an auto paint / finishing / body repair type supply house. These usually include all manner of widgets and trim clips and fasteners sold in bulk.
I'd try that route for NOS, or to eyeball something close that you can mod up for your app.
OTWI (Off The Wall Idea) If nothing available new or left at the junkyards then maybe drill out the studs with a hole, - glue plastic studs (use plastic model parts sprue) to the back side of the trim at the said new body holes, - and use a tin speed nut like what holds on the front grille and bottom door trim hangers?
\'96SS SOB: SSRI, Herter Tune, Tri-Y II, , 3000 Edge, F/HO bars, METCO extendeds with CV MMC, Bilsteins, currently Vredestein Ultrac Sessanta (315/35 rear). Finally, wait for it... LT-4 knock module!
\'96FWB BUW-Butt Ugly White: PCMPerformance tune, HDFA w/ swissed filter, 1/2 SLP s.s. catback with H- and Flow Super 50s, oem opti rebuilt 3 times, SS Bars, METCO LCA, Airlift 1000, Monroe SS, PowerTrax No-Slip, CTS wheels with +1 rubber. Finally, yes again... LT-4 knock module!