This is so that newsstands can sell a magazine released in March before the next issue is released.
To help explain this further, imagine you go pick up a magazine on April 13th, and that magazine's new issues are always released on the 15th of a given month. By labeling newly released issues with the next month's name, they will sell you an issue labeled "April" even though it was released in March.
So basically, just wait until December 6th like the picture said. That's when they'll release the new cover.
Frankly, I think it's Uncharted 3.
I don't think he was confused about how the month stamp worked. He just hasn't gotten his december issue, so he isn't sure why people are talking about a shipwreck cover when the december cover is the 30 characters theme. But tennyson, december is the characters and then they had a page inside the issue that had a preview of the jan. cover so yes the soonest we could possibly see a GI cover is on the Feb issue.