I have bought an engine with the mounts in place but one side has a metal plate under the mount where it would meet the cross member and the other one is just rubber. Should both sides have these steel plates/shims or is it OK to mount the engine with rubber making contact with the cross member?

V3 STI Engine btw.

 

I'm pretty sure that is correct as the one with the shim/shield is to protect it from the heat that is created by the headers

 

I had shims on both sides last time i removed my classic engine.