The governor appears to painted "black", originally (i.e. late 30's) they were painted gray. The gray paint was to indicate that it was an engine accessory, stayed with the engine when removed from aircraft. Then they were painted black to indicate that it was not part of the engine.
The governor is missing the head, so unknown if it was an electric head, used on B-24, or the mechanical head with a pulley and cable to change the propeller pitch, like the C-47, B-17 used.
The governor appears to have the parts needed for attachment of the feather pump line, the boss is broken off of the body, and the gasket for the cut-out switch on the base to turn off the feather pump when it hit the required pressure, i.e. the propeller has hit its internal feather stop.
There is no coupling visible coming out of the base to the engine mounting pad.
The Merlin and Packard engine had internal splines in the drive gear, so the engine mounting pad had an external splined gear coming out of center of the pad.
The radial engines, R-1820, R-1830, R-2600 had a internal spline in the mounting pad and the governor had an external spline that came out of the base of the governor. It was either a removal spline adapter or an adapter attached to the drive gear by a retaining wire with three ears to drive it.
The relief valve is the very early design before they changed to a different design, with a longer relief valve cap.