ChromaVision®is a portable, computerized color matching system that views and reads the actual car color, then transmits the reading into the ColorNet® computer system.Other paint suppliers have them too. (Basf,PPG,ect)
http://pc.dupont.com/dpc/en/US/html/visitor/b/dr/s/color/cmt_chromavision.html
The jobber who supplied my paint had one of these (do not think of buying one lotsa $$$)anyway if a local auto paint supply has one of these they can scan your paint and come up with a formula not sure how well it works for backglass though,but for cabinet and playfield colors I do not see a problem.