K-2. - I have had the boat only since early July, haven't had it on the water yet ( that's another whole topic - pretty in-depth restoration). You are correct about them being mechanical. Chrysler had a "hydraulic" option back then that is a bit funky. As with typical mechanical reverse gears these are common with the engine crank-case oil. There is a hydraulic shift mechanism on top of the mechanical gear. Essentially there is a hydraulic cylinder (run off the engine lube oil pressure) that has a fork which shifts the mechanical gear. With this you have a typical 'teleflex' type cable that runs to the helm, when you shift F-N-R you are changing the valving to the cylinder, which then shifts the mechanical gear. I have the full Crown manual and it does discuss the adjustment, but it says there is some trial and error between adjusting the hydraulic portion and the mechanical gear, sort of a balance point between the two.
Oh, and I don't know who actually built the gear. It could actually be Chrysler, (they built so many Aces, Crowns, & Royals over the decades.