I've looked through the parts catalog and do not see the 2 1/2" round inserts listed. One is located directly in the middle of the play field labeled The Sun", and the other near the pop bumpers labeled "Increase Energy Value".

Both measure 2 1/2". The inserts are shown on page 7-6B, but these aren't listed.

Also the one near the pops is located under the mylar. What's the trick to removing mylar without ripping off paint?

Pinball life inserts worked perfectly. An inverted can of compressed air worked great for removing mylar.