fiav block off

hey guys. I have a 1g throttle body on my 2g and have been experiencing high idle (2000rpm). I already have re-routed my coolant lines so they don't circulate through the fiav, but i know it can still be a boost leak point whether those lines are hooked up or not. They do sell a plate that retains the iac, but since the iac housing is a part of the fiav i would imagine that you have to put the block off plate in between the fiav and the throttle body (Unlike the complete block off plate where you just completely get rid of the lower portion of the fiav). My question is; if you are sandwiching the plate in between, how does it seal? Is there a gasket for the fiav where i can just buy two when i install the plate? Or would i just use hi-temp RTV? Thanks guys. As always I appreciate your help and expertise.