Vacuum hose question

I have a small vacuum hose coming out of the vacuum switch on the airbox and it is disconnected. I have a small.port on the side of the carb but I am not sure if it is correct. Some pictures attached to maybe clarify.

I am not familiar with those carbs, but the open brass port looks to be a bowl vent, judging by what appears to be a cast-in tube going to the top of the float bowl. A bowl vent should be open to atmospheric pressure, in a turbulence-free area of the bike... usually up under the seat or tank. It must NOT get connected to the emissions equipment or to the inside of the air box.

The vacuum ports on the emissions control valve usually go to a manifold vacuum port, which has intake port vacuum on it all the time. It usually gets Tee-fitted to two of the four intake ports.

It looks like the metal part of the emissions control valve is already connected to a vacuum hose.

I can't really tell what the little plastic port is connected to... the airbox maybe?