Confused Ignorant Journalists
There are a bunch of really buggered up English language versions of this story on the web. It turns out that the brick only has a Calendar Round not even a Long Count on it and it has no distance glyphs to indicate it refers to the future. A Calendar Round is a combination of a 260 day ritual calendar and a 365 day vague solar year with no leap year. It can only specify a date as far as 18,980 days or 51.9641 solar years. See:
http://en.wikipedia.org/wiki/Maya_calendar#Calendar_Round
The Calendar Round on the brick is 4 Ahau 3 K'ank'n. Yes this is the same CR as the one that will occur on 13.0.0.0.0. Does this mean any thing? No, Not according to David Stuart, one of the world's leading experts on Mayan epigraphy and participant in the Palenque congress. Still the media went wild and reported that it did.
This is B**l Sh*t.