Drum brake spindles
I think so. I know a lot changed in '73. These are stock 1974 spindles, for 10" drum brakes and 4" lug pattern (small bolt) wheels. (I also have the 10" backing plates for sale if you want those.)
Here's a closeup of the stamp on one of them, in case it helps. It's a bit hard to make out. I can try to get a better photo if that would help.