I purchased from the dealer front and rear pad sets with which to do a brake job on my 2000 Outback Wagon. Front set had two sets of shims (4 black and 4 silver), two tubes of anti-squeal paste, and instructions. Rear set had only one set of shims (black), no paste, and no instructions. Am I missing something?

I forgot to mention - each set also had 4 guide clips.

While shims are useful to reduce squeal (a layer of brake lube in-between the shims and the back of the pads will damp out the noise), new shuims really aren't absolutely essential for the rear pads. I've been running my '96 OBW with aftermarket pads on the rear for years. They don't come with shims and I just reuse the original OEM shims that I found on the original set of pads.

 

They work fine that way.

same here on 20 year old 80's subaru's. still rolling with original shims and clips. pad slap them and away you go. i've seen very few brake issues with subaru's. none of the 12 or so that i've put significant miles on have made any noise.