1. 3-4 weeks out is usual, never less that a week.
2. Concur rate (have to use it). I don't rely on a freebie upgrade. I book the room I want, but even then I am not getting what I booked, such as a king suite, high floor, not near elevator. It's very frustrating. Either concur is not communicating the room preference in a way Hilton understands, or maybe Concur is "re-faring me". I should try to book direct, it's normally the same price give or take a few $ and just deal with the exception....