Couldnt help myself had to get rid of the Mylar Asap,

came off reasonably well without damaging the artwork,

but took most of the insert Art with it,were these Just decals from factory?

Seem to be an addon very yellowed, can scratch them off with your fingernail..

Used a combination of freezespray and the Hairdryer to get it all off..

In relation to the artwork on the inserts, they are in fact screened on as part of the original artwork.  Now that the mylar has been removed and the screen work has come off it, I would say the inserts will need to be removed (if they had to be leveled anyway), wet sanded as 48 has suggested then re-glued.  Now I do believe Jeff from Classic Arcades has the insert decals for these (not sure if the proto playfield is different).  I found sometimes the inserts are off slightly and not always 100%.  If you are planning to 2k clear the playfield, I would strongly recommend to buy the NON LAMINATED ones.