The dealer's service department would put the plate in a holder and use it to emboss a block in the service order. I just looked at my old receipts and found one of my warentee repairs that has my Protecto Plate image on it.
On that order (7/69) they replaced a cracked steering wheel (sound familiar), new top switch (sound familiar), fixed the AC (the worse part of the car since I bought it), fixed a leak at the windshield to convert top (sound familiar), and removed a couple door shims to fix a door rattle (they said that was a common fix because the factory put too many in).
