Yes, I agree its most likely from the 1950s or 1960s. I am not sure what kind of info you are looking to find out about this piece. Check Amazon and see if anyone has written a comprehensive book about GP (you might find it interesting). I have one for VC, and it has photos of dress watches, reference #s, and a few other things, but truth be told, there isn't a lot beyond that about older vintage pieces. You should try bringing it to a GP boutique, if you live near one or if you travel someplace that has one. Give them the ref # and with some research they should be able to tell you more about the watch, such as when it was made. However, I doubt you will find much more than that. There just wasn't a lot written about some of these dress watches back then.
Great looking watch. Enjoy it!
Excellent info and advice; thanks!
Excellent. Working hard and enjoying IRL existence... so not online much.