The transmission mounted brake is very reliable and should be easy to find, whole transmissions with brake sell for what, about $75?
The foot lever and stuff on the drivers side floor may not bolt into your cab if the cab never had that before. I do not recall which years or models were setup for the left floor mounted brake lever.
Along with that you'd need the cross shaft behind the cab, brake cable brackets riveted to the frame up close to the front end of the rear leaf springs. Plus all the stuff in the rear brake drums and the correct backing plates to use cable parking brake.
So, if you already have the left side brake lever, all the linkage and stuff in the drums then sure use it.
If you are searching for a parking brake and have nothing now then transmission mounted is the way to go, simple and cheap.
Grigg