Re: vintage banjolin questions
The "block running through the body" of a banjo is generally called the dowel stick. If it has a "Maybell" imprint on it, that's the manufacturer's label, and your banjo-mandolin was made by Slingerland. Slingerland and Lyon & Healy were both Chicago firms, and it wouldn't be at all unusual to have an easily-added part like an arm rest, made by another manufacturer and added either as original equipment, or subsequently.
Don't know where you're located, but it might make sense to visit a music store that has a good repair department, and get some hands-on expertise in fitting a new head. As Mandroid says above, if by "restore" you mean to make it "authentic" or close to what it was when it was new, a calfskin head would be preferable. If you want to avoid the humidity and temperature sensitivities associated with skin heads, a plastic (usually Mylar) head is more stable, and can be thinner, thus producing a brighter, less "thumpy" sound.
If the flesh hoop for the old head is still on the banjo, this can be your template for the new head, and also the frame around which a new skin head would be fitted. The bracket hooks of the banjo hook into the stretcher band; take this off, and there may be a thin metal hoop or ring under it. This would be the flesh hoop. I assume the resident rodent would have consumed all the organic material associated with the old head, but the flesh hoop might still be there.
You may have problems finding a pre-made plastic head that will fit your banjo, but if that's where you want to go, investigate the larger acoustic instrument parts suppliers. Again, a good professional repair person would be quite valuable.
Good luck with the instrument! If you get it restored and playable, be prepared for a torrent of abuse for the large majority of people who don't seem to care for the banjo-mandolin...
Allen Hopkins
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