I want to see the bottom.....and a picture of the fixture part.....where the light bulb goes and how it's set into the brass thing.

If the lamp socket shell is original (brass), it would be very helpful to see a closeup shot of the shell outside and inside. The composite plugs usually date before 1930 - they started using bakelite for sockets and plugs around this time.

You can still buy that style of plugs at any hardware store today

You may find plugs that resemble the style, but not the material, of the old ones. Also, new plugs are generally UL-approved and are therefore differently designed (e.g. polarized). It's a little hard to tell with the one being discussed as there's no closeup or side view pictured.