GM also used channel stuffing to make its "sales" look better than they truly were.
Link to a good op-ed on this: http://directorblue.blogspot.com/2010/12/tres-awesome-did-gm-pull-off-its-ipo-by.html
Another reason to stay away from the stock. Channel-stuffing is a big no-no. I once read a book on how to spot disasters/chicanery in the making, and channel-stuffing was one item mentioned.
A rhetorical question: why is it that GM acted most like the stereotypical corporate-basher's portrayal of the "wicked corporation" when it was majority owned by the government?