I eschew any items of clothing that tip others to my gun interests, except of course when these interests are already obvious, such as a training session or etc. The more unassuming and harmless I can appear to be, the better. On a rare rainy day awhile back, I grabbed the handiest baseball cap, which turned out to be a very nicely made cap, black, with the "LaRue Tactical" logo embroidered on the front, and then headed off to the best local BBQ joint for lunch. Jeez, I felt as if everybody in the place would glance at the cap, read the logo, and then begin looking me over to try to see where my armaments were hidden. Probably just my imagination at work (an infrequent occurrence...), but hey, nobody takes any notice of my "Tractor Supply" or "Boat US" caps...
I regard tee shirts and etc. emblazoned with "gun" stuff as a tactical liability. However, I was quite enamored of two I've seen lately: One, in faux "Arabic" letterstyle reading "INFIDEL", and another: "Alcohol, Tobacco, and Firearms ought to be a convenience store, not a Federal agency."