OER = Classic Industries. Same company. As far as I can tell, Classic is the only one with stock (or that even carries) that part number.
I see differing results on the actual depth of MW925, including on the OER site. The header says 2-1/2" deep, while the description says 2-1/4". I think 2-1/4" is correct. Whether or not they're worth a damn, I'm not sure. It seems strange that nobody else has them.
As far as why your spare doesn't fit: Muscle-era Chryslers didn't come with matching spares other than the occasional C-body. They were either space-savers with the inflator bottle or a plain steel wheel. Later models
were available with matching spares, so they had a longer hold-down stud for the spare. Chrysler even made a center cap for those applications with a knockout in the middle of it for the hold-down stud:
On the cars that came with them, the knockout center caps were used on all five wheels, but only four of the knockout center domes were included--the ones bolted to the car. The spare didn't come with a center. If you got a flat, you snapped the center dome ("knockout") out of the flat tire and popped it into the hole on the spare. Knockout center cap was used in 1977-'78 on B- and F-bodies. A '75-'79 B-body hold-down stud would
probably swap into your car, but I can't swear to that.
The knockout caps were by far the ugliest factory center caps ever affixed to a Rallye wheel. The knockout piece doesn't fit well and is always obvious. They're great for a spare, though, especially if you get one with the knockout piece intact (keep it in the glovebox or console).
Regarding the bumper guards: 99% of the world prefers the 1973-'74 cars
without the gigantic buck teeth, especially up front. It's a personal choice, obviously. Removing the fronts was one of the first things I did to my '73 Challenger back when I was 17. I just put two more chrome bumper bolts in the holes. I left them out back, though, because there are contours in the valance that match them. You can't just remove 'em and call it a day.
Because the bumpers are an extra inch-plus away from the car starting in '73, the better-looking 1970-'72 rear guards end up hanging out in space. There's a huge gap between them and the valance when installed on the later cars. On my current car, I solved both issues by using 1970-'72 bumper brackets on both ends. They tuck the bumpers in close, eliminating the need for those huge silver urethane fillers between the bumpers and body on both ends. I won't have front bumper guards a'tall, and out back I have the flat chrome guards (no rubber) used in 1970-'71. In my case, I also went with 1970 bumpers to get rid of the unsightly jack slots. I'd never use a bumper jack on the car anyhow. I'll keep a trolley jack in the trunk for emergencies.
Here's a 1972 'Cuda with the factory tucked-in bumpers, no urethane fillers, no front and small rear guards:
Here's the later bumper/guard arrangement used in 1973-'74 only. This guy painted the fillers black, but they were always silver from the factory regardless of body color:
The bumper guards and fillers weren't installed because they looked good (they don't), they were installed because the Federal government enacted unrealistic bumper laws starting in 1973 and tightening them further for '74.
