I don't really think the way you brought it up was a problem. You don't want to go into an interview saying immediately, "Okay, what's the pay, that's all I really care about." Likewise you don't want to state pay requirements in cover letters, as said. But asking at the end of the interview especially when one of the interviewers has been making a huge deal over salary, I don't know, that seems okay. In my experience, if you want to know, you can't wait until they bring it up, because they usually don't bring it up in a direct way. Not until after you're hired.
On the other hand, I have had interviews where the first thing out of the interviewer's mouth is, "What's your current salary?" I consider THAT kind of rude, personally.