Need Help! Front Bumper Identification (pictures)

Well, the hits just keep on coming. When I bought my Swinger about 6 years ago, the front bumper was in the car. There were no mounting brackets. I bought front bumper mounting brackets for a '73 Swinger from a member here and cleaned them up, painted them nice nice, and thought I was good to go.
Well, this past weekend, I tried bolting the bumper to the brackets and it looks like the front bumper is too wide by at least 2-3 inches. Furthermore, it doesn't fit the brackets correctly. Below are a few measurements:

Width (along the top): ~68'
Width between top outer bolt holes: ~58"

I did a little research, and it looks like the bumper I have fits a '74 Valiant. Tell me what you think based on the pictures below. The first ones are of my bumper, and the one on the red car is a '74 valiant I found online. The last one should be a '73 Swinger. Am I going nuts!?
Thanks for any information you might have.

-Mike