factory tach and AIR pressure gauge????

[sigshooter]

Ok guys need some info here.... I found ( and bought ) this gauge cluster in a junk yard in Missouri today while visiting inlaws for T-Day. It came out of a 1 Ton but has an air pressure gauge, did it come from a 2 ton to have air brakes? I just bought it for the factory tach but figured someone out there would want the air pressure gauge.

So what did it come from originally? I cant remember ever seeing an air pressure gauge. Are these rare ?

I also found this unfinished Cobra sitting in tall grass with a TowBar still hooked to the front. I am working on who this belongs too and what they want for it. They obviously dont value it much if they just leave it sitting outside in the weeds with a tow bar still hooked up.