i had a friend over with her shih tzu (a rescue dog). he's 2 yrs and a few months old and neutered about 6 months ago. he did mark indoors and outdoors. he marked on furniture in the lobby when he arrived, he pee'd over my puppy's stains on the potty pad, and he tried to mark me but my friend stopped him before he did!!!
just to be safe, when they were over, we kepted the both of them in the tiled area to play.
not sure if this behavior is because he's a rescue. since he's neutered now, the marking is probably out of habit from when he wasn't neutered. but just to be safe for you and your home, i'd strong recommend that you keep the new doggie confined in an easy to clean area just in case.