either way it's a Westinghouse design, but this is more likely Westinghouse because the Cooper NEMA tags didn't loose their numbers like this. The Cooper NEMA tags were actual foil with the numbers printed right on it. Some of the Westy NEMA tags were too but others weren't actually metal, they were polyester with a metallic colored laminate over the top that peeled off a lot of times. The Cooper ones just lost their gold hue (ditto for the GE ones, which were actual foil as well, but Cooper's NEMA tags were much thicker than GE's).
And now for a little trivia, Who can tell me the most obvious difference between a Westinghouse OV50 and a Crouse-Hinds OV50 (Not the OVM, the OV50 was still silver)?
The position of the photocell socket. The Cooper OV-50 had the PC toward the rear and when they renamed it the OVL and painted it gray they brought the PC socket back to its original position. Not sure on interior changes though since I've never seen the inside of either one up close before.