Lamp looked like this?
PAR64 : Light Bulbs at Bulbman.
Socket like this?
PAR 64/56 socket GX-16 - Lamp Sockets - Lamps - LAMPS
As for "convertible key," see key light. Not sure about the convertible part, may be that the light can be converted into different beamspreads (by changing the lamp).
So the Cine King really appears no different than the Cine Queen.