Neat old Alemite Highpressure volume pump, looking for years used.

[wrenchguy]

Its handcrank and pump handle, from what i figure you would crankup the grease to the top of cylinder and then pump it using the pump handle. The "id" of the bayonet fitting is 7/16", is that common for cars? I think i'm missing a fitting that goes on the small petcock type valve. Maybe its a vent??? I know tractor volume compressors had a fitting for the hose end to connect too when one was done. The fittings at both ends of the 5' hose swivel for ease of connection. Would anyone know what years these came out. I guess the repair shop would keep these around just because the older cars still needed grease. I think this maybe a long shot, but anyone know what model this might be? Thanks for any help.