Some people buy the IS rear pads for their tourer or standard because they a a couple bucks cheaper, but the standard pads have an anti squeal pad......I agree with above....clean all that junk off and make sure you have the right parts
I bought the pads for a std, not the IS pads. I'm assuming the anti squeal pad to which you refer is the thin aluminum (looking - don't really know it's composition) plate on the back of the pad. My new ones came with those.
Thanks to both responses. I'll remove, clean the surfaces and reinstall.