The first sign that this date is important is the calendar in Carpet Diem, in which the date is circled.
We know, from several clues, that the show takes place in 2012.
Here are several references made to something in 1982 or 30 years ago:
Alex said in his AMA that Stan has been practicing the same card trick for 30 years but he still can't master it.
Stan says at the beginning of Scaryoke, "Thirty long years and it's all led up to this."
Agent Powers (I think) said a few seconds later that they haven't seen readings like that in 30 years.
In Boss Mabel, we see the book "Succeeding in Management 1983" which is close to 1982.
