Well folks I finally got the bumper list. They are nearly all 70's and 80's. Couple of late 60's bumpers, and I know theres a full set of 57 chevy's and a set of vette curly's. But that's about it. I was hoping there'd be more older stuff. Sorry.
oldest cutlass bumper is a '74. Got a couple of '71 gm bumpers. Check out interchangeability. I've got no record of anything else to fit a cutlass.