Personally, I find that even the more short-tempered box office workers will at least tell you where the seat is. I have, occasionally, asked about rush seat location before buying, and they have always told me. For me, the real variable is whether or not they let you choose between different rush seats. THAT always depends on the mood of the employee, and/or the show's policy. But it doesn't sound like that's what you're looking to do. I think if you make it clear that you're deciding between the rush seats and full price, they will tell you where the seat is, even if they are a little grumpy about it.