Yes, most definatlely call UA once you hit 1P and have them
re-enter you MP number, as you'll then zoom up the list (well behind 1K/UGS, but up the list nonetheless.) NB: Give it a week or so, as the MP and reservation systems update seperately and it can take a bit of time.
Others have reported the 72 hour palaver before and HAVE lost upgrades because of this. At least the agent was upfront about things. Better that than not knowing about the requirement and losing the upgrades. See last post of this one as to what happens when you don't call:
http://www.flyertalk.com/forum/showt...e+call+confirm
One word of warning if you do not clear in advance of the flights. Your wife (I'm assuming does not have status) will carry your status BEFORE the flight. On day of departure, if you have not cleared, you will go on to the Departure Management list (DM list) at the airport. At that point, it goes by INDIVIDUAL status. Thus there is a likelihood on one of you clearing (i.e you with 1P status) and one of you not (i.e wife without status). Just another 'gotcha' to be aware of with MP upgrades.
My guess is you'll clear the 763 without problems. The return may be a toughie, if it remains a 319 (only 8 possible F seats on a long route).