Disclaimer: I've never used a RUC I just read this forum too much.
RY (formerly RP) is the booking class used for mileage and certificate upgrades. RU is for complimentary medallion upgrades.
Your RUC will only be marked closed once the flight is reticketed (different process from clearing). You can tell if you were reticketed if your ticket number has changed from what you were emailed when you originally booked your flight.
There is some anecdotal evidence about clearing into RUC space and having a valid ticket but not having the RUC closed, however I wouldn't count on it. If you want to make sure everything is in order the right way, I would call reservation and ask them to make sure the RUC has processed correctly, if you want to hop the RUC stays open, I would say nothing.