My '48 14-13-3 has an electric motor to operate the otherwise manual gear. Don't know if it's a factory installation, but it's obviously been in the plane a long time.
The motor is located under the co-pilot's seat and held against the landing gear bicycle chain by an apparatus that is welded to the seat frame and spring-loaded to disengage the motor from the chain [so the gear can then be moved in the conventional, manual manner] by pulling out a "pin" that is accessible from the front of the co-pilot's seat, under the co-pilot's knees. Actually, it's not a pin: it's a crank handle for re-deployment and use in the manual retraction/extension mode. I say "a" instead of "the" crank as another crank handle is still in place in the conventional location [yes, it spins when the electric motor is in use]. In fact, I sometimes use it to "help" the electric motor, which keeps popping its circuit breaker -- but that's another story.