Nice !

Looks to me that it COULD be contact - not mylar. If it is thin - it is contact, and it MAY come off easy. Look for "ball swirl" under the contact/mylar. If there is evidence of wear under the contact/mylar - then I would lean towards leaving it and consider the Treasurecove polishing kit and some general trimming of the contact/mylar.

Maybe try a test spot first and see how you go. You might have a pristine playfield to match the backglass !

By all means - start a resto thread