Is this not a turbo pump?

[chris24g]

The aneroid does not have the barbed fitting for boost. The small port on the side of the aneroid where I thought a line would go is sealed. Or appears not to be tapped through. 

[vanbcguy]

There are some NA pumps made with aneroid castings, but they were never actually machined for aneroid parts. If you open the top and find it empty that's what you have.

There's also the altitude compensating pumps which have a similar setup but have a pressure cell plumbed to the bottom rather than the top of the space ship.

[chris24g]

Ok, I always thought if there was a UFO on the pump, it was a turbo pump. Thanks for enlightening me. When I get around to opening it up, I'll post pics.