There is a distinction between prototypes or pilot machines and regular production games (not even counting the initial whitewood). Artwork and details can vary from one proto to another of the same machine (I've seen three Capcom Kingpin protos and each one had different coloring in the playfield artwork). Scared Stiff pilot run games had numerous details (that we all know about and love - good thing that other people have offered most of them as replacement parts) that weren't in the production games. Capcom made 14 proto Big Bang Bars but never made any regular production games. Gene Cunningham made the first actual production run of BBB, albeit limited to the board sets he had available. I would not call Gene's BBB games remakes.
And now the world will come to an end, because I never thought I would ever agree with teekee about anything.