Im Not sure but i would say calf skin was the heads used. The heads as seen are modern and fit fine. All premier snare drums are fine with international heads was just a stupid time when they were pre international for a while.

I saw a flor-tom with springs on the resonator membrane, but here I see the drum with springs under the shock membrane and the resonator membrane for the first time. When can I see and listen to its sound?

You nailed it. Glad you kept it aged.

Thanks Oddball for your input much appreciated. The drum now complete is a great talking point in my house. I dont allow any old idiot on it (apart from me hahahah) but now and then let a few people loose on it. I actually took it out on a rehearsal and wow what a rock sound from this 1930's beast. It came from an era when drums were made by craftsmen. Today we have some fine drums but they all look the same and basically most sound the same, you just pay different amounts depending on what badge it has tacked on.