Got my answers, thanks. The drum was very tight. Chris, the owner of Wheelworks(not the car shop) is an old-timer out here in the SF Bay Area (40+ years) re-lacing rims. He helped me at his shop get the drum off. He primarily restores BSA and Nortons, but knows all wheels inside and out. He echoed what Carl said about tight fit and Tim said about bare steel. It's like an episode of American Pickers meets the wand maker in Harry Potter with a ton of British Bike parts everywhere. Very eccentric dude.
I'll post pics of the progress of the bike soon. Color is not exact, but considering I had it completely blasted and powder coated, she is all metal, zero filler, and it's something I would have picked had I purchased new.
Thanks again, Carl. And Tim shoot me an email when you come up for air and let me know how you're doing.