Front or rear?
The rear bumpers are completely different, the ‘73 rear is the same as the ‘70-‘72, much narrower, much lighter.
In the front, I’m not 100% sure. I had a ‘74 non-shock mount bumper. It looks the same as a ‘73 but with different mounting holes. But that’s going from pictures and cars I’ve seen in person but didn’t measure, so it’s possible the width is slightly different. I kinda think the ‘73 front is the same width as the later ones, but I haven’t measured them.
