Call and ask. Up until a few years ago, you had call and/or get a form to fill out and fax to VIP Services so it's not a real rigid setup. Even having a ticket now, I don't think I've ever been asked for it, just had to give my name and they check the list.Has anyone had success requesting a specific tour guide in advance? I really want to get Kelly for my UTH tour.
Also, based on who comes, they always make changes to who's assigned to what groups (provided there are enough people to have multiple groups for each time slot). Go up to her and tell her you enjoyed her tour so much last year and you hope to be in her group again and I'm sure she'll figure out how to get you on her tour (so long as she's scheduled for a 3- or 6-house tour that you schedule).
One year my friend bought a UTH ticket like an hour before tour started, I had purchased mine a month in advance. We went in together and were chatting and stuff until we saw a guy with a clipboard. Went over to ask if there was any way to ensure we were in the same group and he showed us his sheet and next to my friend's name he had written "Nine Inch Nails" which was what shirt I was wearing to make sure he added the late addition to the group I was in since we were clearly friends