Rick is correct. Most don't realize just how many times things occur between prototyping, sampling and final production (let alone actual production variations). PPS has all of the original art, yet sometimes things occurred at the print vendor at the direction of their client (WMS, Bally, Williams, etc) that "stopped the presses"... or last minute change that all occurred AFTER the art was released to the vendor. I have even seen whole plastic parts being ADDED or DROPPED, or shape change. Lots of reasons we can all probably think of... like balls getting stuck and so on. Color changes are a common theme we see, last minute. Some are still visible with some of you collectors who have prototype, or early run games to compare later ones to.
So... yes. One way as a manufacturer we have developed to not get creamed online (by unforeseen mistakes) is to try to cover our bases... sometimes with two to three machines for comparison. It is a COMPLETELY different, and more complicated task to recreate previously printed products using the screen print process (a largely old school process) than it was to produce these the first. time. Obviously, the first time there was nothing to compare to... so it was PERFECT, color... shape and all! Same goes for back glass, cabinet art and more.
Thanks forks for stepping up with sample sets. We have what we need being shipped.