I just got a Twin Win and had the same issue / question. I’m resurrecting this thread to answer it for future owners.

Looking at the schematic at IPDB, there are no lights shown for the pops. Thus: general illumination always lit.

As to the pop caps, there are pictures shown with green and yellow sun, green and yellow sun 100 pts when lit, and the red sun with flags. The poster has 100 pts when lit, green & yellow.

Mine has 100 pts when lit and although someone did a nice restore on the pf, the caps are toasty enough that I’ll call them original. But, I’m going with the flags, because it looks good with the machine's art and flags seem right for a race game.