Most likely, can count on artwork or insert decals to come off ...
Is this original Mylar on the playfield or Mylar around the pops
I've has successfully done Mylar removal on some games however not on others

I would suggest avoiding mylar removal, especially on system 11 games. It is very likely that you will remove the insert artwork. On diner, that's much more difficult to replace than on other games with just text on the inserts.

I removed mylar from my Diner with zero issues using freeze spray. If it is bubbled or lifting, I would pull it. Just my opinion. Mine is not a diamond plate either.

In my experience System 11's are tough. I don't think I've done one where i didn't lose at least some insert art. I have also had 2 system 11's over the years where the playfield was badly damaged due to botched mylar removal. Not worth the risk unless you are capable of doing the restore.

I have actually done a couple sys 11s without issue. My best practice is to blast the full piece you are about to remove first. Then blast the part where you plan on lifting an edge. Then keep blasting larger areas than you pull at a time without forcing anything. If it has resistance blast again and make sure it is not actually frozen in place. Sometimes wait a couple seconds and the resistance goes away.

I think
Freeze works well.

I’d also say that I think some who have issues w art coming up are too hasty in removing. They pull too fast.

Let the freeze do it’s job. Some
Pull the Mylar so
Much.

yes mylar will come off but have fun getting all the glue off the playfield. From personal experience, just leave the mylar.