I have some Gen3 .40 S&Ws with rails and a Gen3 G21 without a rail, and have been thinking of trading the rail-less G21 for a railed version, if I can use the same light across the board. I don't have a light just yet. Are the rails the same width and/or do most light bases adjust for the different size rails? Thanks in advance! ETA, I have searched the topic but did not find the answer, and became distracted by a bunch of other useful info. I found.