Yes it's fine. Just be prepared, you often get vendors selling trinkets crossing the beach, and also groups of people walking to the docks on the left-hand side to catch a boat. Sometimes these groups do include children. If you don't mind the few non-TTR public crossing through then there's no problem taking your top off.
Is it just the sexy pool where woman are topless? I know you need clothes on for dinner, but what about other areas of the resort, like just walking around the grounds (ie room to pool)? I'm a newbie and I'm sure ill find out quick enough when I get there, but was curious so I thought I'd ask now =)
someone correct me if I am wrong but I thought that topless is ok on any public beach in mexico. The bottoms though you have to keep all the naughty bits covered.