I carry a Glock every day but trying to call it the iconic American sidearm is like calling the Toyota Corolla the iconic American car. Just because it sells a ton doesn't make it an "icon" and doesn't make it "America's", as in "ownership".
If it's "America's", we have to "own" it. It has to be what pops to mind when you say two words "American" "handgun".
You don't think "Toyota Corolla" when you say "American car" and you don't say "Glock" when you think "American handgun".
Just the idea that something that's been here for barely 30 of our 237 years could be our nation's icon is almost laughable in it's own right, even if it were "American".