Early drum magazine

This drum was found still in the original box many years ago in the back room of a gun shop. The owner told me there had been a factory recall and the drum was returned for some type of modification and then sent back. I think that this is the first drum magazine manufactured for both the AR-180/18 and Colt AR-15 ?

Also attempting to establish the date of manufacture and any other information would be appreciated. This drum has never been loaded or used. There is a thick plastic see though plate on the back which you can view the number of cartridges still in the drum when used.Attachment 104360Attachment 104359Attachment 104358

A friend has one of those and though we tried, it wouldn't feed quite right. I never had the chance to try to sort it out...