idle air control valve question '99 Sprint ST

Hi again,
As I was checking the idle stepper motor, I noticed that the idle air control valve has 4 air line connectors. Mine only has 3 air lines connected to it. the fourth connector has no air line connected to it and is open. Anyone know if this is proper?

Thanks

Stephen

[Diderich]

My 00 RS is the same. Although when I felt around on the fourth connection (far left when sitting on the bike) it didn't appear to have a hole.

Also, when the vacuum lines to the other three were leaking on mine, there was a lot of popping at idle. It was very noticable that something was wrong.