Hey man,
I was down there the other day looking to switch my UD4 to an ASUS P8P67 Pro. They were fine with that, but they did not have stock of the ASUS board at the time. The manager was even willing to take back my i5 2500k if I would take store credit and pick up a 2600k (natch, this makes them more money;YMMV on this deal, however, and I could not get the "combo" price with the ASUS board and the 2600k). But overall, it was a fine experience.
They did not tell me of any "deadlines" to effect this exchange, but I imagine they have one in mind.