I have a 74 Challenger. The passenger's door window and both rear side windows are stamped with the Pentastar logo and a PPG logo plus the numers AS2 M20.7 26 63 Dot 18. The driver's door is Pentastar, PPG, AS2 M7.8 26 73 Dot 18. I got a used replacement driver's window that is stamped Pentastar DCL AS2 M21 BG69 Dot 19.
What do these numbers mean?