And before you push the pistons in, take the cap off the master cylinder and wrap a towel around it and cover the top.
I have to agree with everyone else. I have yet to see any kind of a spring on a motorcycle disc brake (any disc brake for that matter), and as for the shims, why would you need to replace them? They aren't a wear item. Their primary purpose as I understand it is to help control brake squeal. Hell, back in the day, we always took those off when we changed pads.
Nowadays, I'm a little OCD about stuff like that, so they go back on. What I will do is give them a good cleaning with a scotchbrite pad, and put a little anti-squeal compound on them, and call it good.