I don't put any stickers on my vehicles, in fact I even remove the dealer name off the back if it has one.
I do however occasionally wear items of clothing that are firearms related, and I don't feel the need to downplay the fact that I am something of a gun nut.
Where I live now (Montana) the majority of the people have no problem with firearms and their owners. When I lived in California, I would occasionally run across someone who tried to give me grief about owning guns. I generally just smiled and tried to stay civil while not backing down one iota.
I simply don't feel the need to hide my beliefs from the anti's and the uninformed.