Allan,
I bet you got that good deal for the manifold and YF 2100S that was advertised on Craigs List recently. I tried to jump on it, but being on the opposite coast made it difficult.
I did Kurt, apparently I was the first to call on it, but it took the guy forever to get it ready for shipping.
You are probably correct in surmising that the gasket covers the port by design. It's probably some type of vacuum port but I don't know what purpose it serves.
