It looks like a 6 lug drum, Dave, with the simple throwoff, that Premier used for Olympic as well. Those throwoffs, can wear a bit and then start to bind. Often, the extra pressure needed to actuate them causes the arm to bend and even break. Slipping the slide side off of the lever side will allow you to put some heavy grease on all the moving components and tighten the rivets with a few whacks on a vice or anvil, if required. I fixed 2 of these that were seized right up in this way. Hopefully, yours is in good nick.
The drum probably doesn't have a muffler either. They discontinued putting mufflers in Beverley and Olympic , in the early 60's. The 8 lug Olympic, that I have (in the same wrap as yours----made a little earlier), does have a muffler. You might consider nabbing one on ebay and putting it in. I know, it wouldn't be original equipment but it does do a lot for the drum------those Premier mufflers are very good quality----much like the Trixon ones.