VINTAGE MOPAR FUEL CAP, UNKNOWN ORIGIN, HELP IDENTIFY!

I would remove the two screws that hold the chrome handle from the cap and see if there are numbers or maybe a logo of sorts under the chrome.....
Good idea. I did so and it was a narrow pocket 1/8 wide length of handle. No #'s there , or the surface it was mounted on either. Am trying to rid unwanted junk/leftover parts from thousands of jobs. I have tossed items before, and very much regretted it. I'm sure you know that one. Thanks!