Lou,
the spots are simply genetic variation. With spots, without spots, with some coloration or without some coloration, it is all genetic variation.
Just like Coast HLs, variation has a genetic link. Some CHLs have yellow coloration with or without spotting, while others are white with or without spots. There are some features that are species related only, while other features are genus linked.
You would have to compile a lot of data on the features to find a baseline, mean and mode on the variation. Some features may also be environmentally linked: i.e. adaptation.
Lester G. Milroy III