Excellent theory. Releasing it closer to the election (a la the drunk driving tripe) would have narrowed the time to prove them fake. Of course, it took us less than 12 hours here, so it probably wouldn't have mattered...
In the past yeare whenever these phoney stories like the Plame/Wilson mess were released by the main stream mediots, a Yahoo or Google search showed that these lies/stories had been blogged for months.
The NY Slimes released that series of lies re Plame/Wilson.
In this case CBS was the big time releaser.
When I see a new mainline mediot hit on GW, I do a Yahoo search. Often there are thousands of hits from the leftwing blogging sites re the latest smear.