Nope. That's like saying Microsoft gets credit for Goldeneye, Perfect Dark, Diddy Kong Racing, Banjo-Kazooie, Conkers Bad Fur Day, Jet Force Gemini, Blast Corps, etc. They had nothing to do with the development of those games, but happen to own the company who made those games (after the fact, just like Valve). Valve buys up companies and publishes titles as if they made them themselves. Doesn't matter though since all Valve games besides the HL series suck dick.
cbf listing two examples, only one of which had any new footage being shown off. Not a very good argument against this being a forgetable E3!
WOW MOTION CONTROLS! HOW REVOLUTIONARY!