We are hoping some Evaporust will clean up the drive chains well enough to reuse the existing ones.
A quick look inside the Muscat Corporation "Black Box" transmission left a good feeling, as it all appeared to be pretty clean, and hand turning the driveshafts led to rotary motion. While not conclusive, a good sign the box may be in running condition.
All the lever inputs move smoothly, and the internal clutch plates seem to move side-to-side to provide friction for drive. Unsure of the specifics to do an true testing/adjustment, that will come late, but for now it looks to be in pretty good shape for a 40+ year old abandoned item!