Meprolight Tru-Dot Adjustable Sight

I tried to purchase this sight for my Glock 21 and due to Amazon's policies, they cannot ship this sight to California because, as I was told by a very nice Amazon customer service person, this sight is not CARB compliant. I have checked other online sites and you can purchase this sight in California. Something about Amazons policies will just not allow it. Frustrating to say the least. Amazon has been nothing but reliable, helpful and has always had fast service so this is very disappointing. I would rather give Amazon my business than some other company, but in this case, I have no choice.