The tin plate has two jobs , Its a spacer and a schield for the flywheel to help keep debree out of it, if this is a differant sound than befor you need to take it back apart,if it is in the clutch area you should be able to see what was rubbing . Where ever the noise is coming from you be able to tell by being under the rig whit the parking brake on and have some one deprees the clutch and start it up. Good luck 
It sounds like you are talking about 2 different plates. There is an upper plate that is just a spacer, it has nothing to do with keeping debris out of the flywheel/clutch area. Because once the tranny and engine are mated together and the starter is in place, there is no way for stuff to get into the tranny from the top.
There is a lower plate that just covers the bottom half of the flywheel. It is bolted on after the engine and tranny are mated. It serves no purpose as a spacer. It is simply to keep stuff out of the clutch/flywheel area.
