Got this in the mail today

It has an odd looking fitting where the hinge pin for the air door goes. Otherwise looks like a good candidate for a rebuild.

can you show me on the pic where?

Oh, you mean the hex bolt on the data plate side. I know on the one you rebuilt, that fitting has a slotted head.

Right, and the correct one has a 1/8" axle in the middle of the brass fitting that is the pivot for the air door. If you have just a plug, maybe the air door is missing too? Or it could be someone has figured a way to jury rig an axle in there to allow the air door to function normally.

I looked inside . The air door is there and it pivots up and down.