They look like the tiny C-clips that go on the regulator valve pin assembly.
Well, that part isn't supposed to be in the on-off area. It
Definitely remove the shims. They can cause leaking that requires you to use a carrier size that is too tight. Remove the shims and retune the level
I have not actually replaced the on off orings yet. I will try replacing the on/off top orings later this afternoon to see what happens. Also here is