Yeah it has normal vacuum-operated powerpiston. Thank god!
When I got it I was about to discard it because of the electric tower coming out of the air-horn, but dis-assembly showed it it normal, part from that aneroid.
I have an idea it is a truck-carb from the mid 80's.
But was thinking, since the aneriod is controlled through a 2-pin plug, it could be an on/off device. Maybe it could be used for benefit with some sort of homemade switch...