I have an old Yucca from the forties which was my unlces. They are rare, and I have not seen many of them. They are much smaller than the ones from the fifties. They have none of those rings you see on the one you have. I couldn't imagine how they put up what that small thing.
I also have my dads from the late fifties early sixties and it is a bigger one, the one I would assume you have. And I bought the one they released from the catolog a few years back.
I brought it camping it's not a bad bag. I prefer it better than most normal size day packes. And its a great pack for c