I grew up in Key West, so seeing shirtless men was the norm. It never offended me one way or the other. Men carried a T-shirt tucked in the back pocket in order to enter bars/restaurants/stores etc. My BF at that time worked outside, and Lord knows you cant do manual labor in KW with a shirt on!!
Northern Girl now: My current BF wears a T-shirt all the time, even at home, around me only. Its his "norm". Which i find strange.
so...no....youre overthinking this....its just a shirt. Theres no need to put one on, when friends visit.
Unless, of course you feel uncomfortable...which might be the jist of your question.
Kinda like i feel uncomfy if friends drop over and im in my robe--i change...I mean....its my ROBE.... lol.
If YOU feel uncomfy---put a shirt on. But dont worry about others...they might just like the view. (wink)