Stephen Reid gave a response:
We'll investigate this, but there has been no change to the release date for The Old Republic - December 20th is the release date for our current launch countries.
While we ensure messages are communicated at the corporate level, we can't be responsible for making sure every member of a big organization like GAME is aware of things like this. We rely on retailers to get that information out to their staff.
Regarding the GAME website, it's possible that their system doesn't automatically allow for a release date that's not a Friday. We will look into it, however, and if there's any specific date change for GAME we'll let you know.
What is interesting is the OP asked if the grace period for registering your key would extend to the 23rd, but Reid did not respond. There was then speculation that the grace period was 10 days, but we have had no confirmation about this anyway.
Given the game is out close to Christmas, a traditionally busy time for post (ie post is broken badly in the UK), the grace period would be a week or so, so those of us who have mail ordered can get time to receive our SWTOR packages.
Update: It was just a glitch and the GAME website is back to showing the 20th. Still no word on that grace period Mr Reid...