Why do you think that the '3) non gradient, polarized' lenses aren't polarised?
What we have here is a failure to communicate. I said " if your Drivers have a brown GRADIENT lens then (apparently) they are NOT polarized." This would be 2) in my list. For 3) the Serengeti web site clearly describes these as having brown polarized lenses, but says nothing about GRADIENT, suggesting that polarized lens do not have a gradient tint, and implying that Drivers with a gradient tint are not polarized. Is that perefectly clear?
I am belaboring this as all the Drivers I have owned have a gradient lens and are hopefully not polarized. Trying to put this to rest once and for all. Thanks for your patience! This has been a challenge to pin down as the Serengeti web site doesnt seem definitive and the online merchants who sell these seem to be even less infornative (Amazon).