I remember the old days when Dad would pick up the NIB machines from the docks. He would unpack them in his building and then assemble. Test for 15 minutes and then strip ALL the playfield parts and roll down some Contact. He made a tool that "cut out" the mylar around the posts, so that when the playfield was re assembled, the contact would not "curl" and lift. I vividly recall the day he lined up a couple of KISS, Paragon and a Dolly Parton and installed the contact. Often, multiples of titles were done to ensure re assembly was done properly.
It was funny to see the Paragon have the contact installed as the standard width of the roll of contact was too thin. A second roll was used, and the "join" was perfect ! Years later, I removed the contact to reveal an exceptionally nice playfield.
The first NIB machine he did was Stern "Pinball" in 1977. First NIB Bally was Eight Ball. He also did a Solar Ride around this time - Which I found in storage 10 years ago. The contact took 20 minutes to remove and uncover a perfect playfield.
He had tested it on EMs for a few years after he found the playfields were wearing out too quickly.