Scott, the lugs are single sided insert just like the lugs on regular floor toms. And yes I still do have that set, thankfully! ( I almost thought of selling it recently)
I hope to get a photograph of this drum set with the original owner's band at a gig back in the early 50's. The son of the owner of the music store where these drums were originally ordered has these photos, when I get them I will post them along with a story about what I learned about them.
Mike