82 Spectre Shaft Drive N1 Carb Vacuum routing?

I have a 1982 Spectre 750 Shaft Drive N1 with Keihin CV34-4 carbs us model. I just bought the bike and doing carb cleaning service and sync. There is the vacuum plug on carb #2, and 3 vacuum hoses to other carbs. I thought the plug was supposed to be on carb #3? Thr hose is long enough from petcock to go #3, but still thinking it should go to #2, and plug should be on #3. Please help

Typically, the vacuum ports on 1 & 4 are capped, 2 is connected to the fuel valve (petcock) and 3 is connected to the Clean Air System, but in reality it doesn't matter as long as the ports not being used are capped.

At Partzilla the carburetor assy diagram seems to show that #2 has the plug & #3 the petcock vacuum line, but it doesn't matter.
The clean air system vac lines would be connected to the #1 & #2 vac ports.