It's difficult to conjure up every available option for the G-body variants as some had mounting "bosses" (stands) and some had more like mounting "bumps" for things like cruise control transducers (83 and below as 84-up has electronic cruise), washer tanks, rad overflow tanks, etc. Even later when they started bolting on the CCC stuff to the little bosses on the wheel well liners.
Knowing how GM approached a lot of issues, they built the cars with parts made from vendors that had all the necessary mounting points for peripheal junk to hang off them, so they may have had several different part number variants of the same part in the factory as the cars were assembled with different peripheal mounting provisions. But when it came to the replacement parts, they picked one set of part numbers that would fit the most applications without doing anything and that was deemed the replacement part. IIRC, Olds Cutlass 2 door used 2 completely different p/n's side to side instead of the sequential p/n system you normally see for a R/L situation.
This is why sometimes when you buy a GM over the counter replacement part for your vehicle, it's the right part number, but it doesn't look exactly like the part that was originally installed on your car. But it is designed to fit and function on your GM vehicle, and that is the only "guarantee" they make about Genuine GM Parts from GMSPO. And unless they changed their warranty, all over the counter GM parts came with a 12 month, unlimited mileage warranty against defects in workmanship and materials (unless otherwise stated, like 3 yr batteries, some drive train parts with mileage warranties, etc.). So yeah, those rubber inner wheel well flaps I got back in 1997 have long lost their warranty.
Based on the parts information, it seems they only made ONE part number available for MOST applications per vehicle in the books. Obviously to minimize stocking parts, and keeping costs lower. It's still a GM part and would fit and function as it was supposed to, but it may appear a bit different than original.
And here's a real kicker that not too many people are aware of about GM parts...you've seen the "remanufactured" parts they sell, like alternators, starters, ECM control boxes, etc., but did you know that they used to remanufacture at least some of the Oldsmobile EMBLEMS and sell them as new?? I've ran across several of the stand-up hood/bullnose ornaments that make me wonder about the peg that the speed nut holds them down on the front of the car has what appears to be "ghost threads" under the chrome. Where they built up and re-chromed the piece, it appears. The factory units had a green, anti-corrosion film they appeared to dip the hold-down pin in. None of the ones I have with the green film on them had ghost threads. But some of the others do. Still appear new, however. Just makes me wonder. I know they did it to the older 442 metal emblems they used from 69-73. I always wondered why they were still listed as available 30 years ago in the early 90s. Which was cool, because I started buying those up too. But looking at the back of some of them, you could definitely see the ghost threads on these supposed brand new emblems. Originals had more of a satin or flattish black inlay on the numbers, but these had a more glossy black. Still look great, but you can just tell that they've "had work done". If I get around to it, I'll yank some of them out of the boxes and take some pics.