I bet they did it fix the annoying rattle the old style idler arm makes.
What size shim is it? I have extra bushing I picked up for this mowing season waiting for the first mow of the year.You have to watch the parts for sure. I bought a new Steel bushing for my 54HC deck pivot arm and I'm glad I didn't take the old plastic ones out of the arm and ruin them,, the steel will not fit at all. Totally different size and wrong part. Plastic is what we are struck with if you have the older deck. I ordered four plastic bushings and two shims just yesterday.