I recently picked up a couple of these to swap out the original part on my 7" FSL.
https://www.mikeselectronicparts.com/product/384pf-air-variable-capacitor-with-81-planetary-reduction-drive/
They "look" almost identical to the part Gary calls out above, but are considerably less costly. Mounting hole are the same and specification, including the reduction drive seem the same.
Anyone care to take a look at let me know if my assessment is sound?