While it is possible for it to come out then never listen to stores. They have changed that date constantly in the past 6 months.
This is the lastest from Gabe btw:
Right now we're targetting a July 30th release candidate. This means we give what we think is a shippable version to VU. Usually you go through a couple of RCs before you reach Gold, which means that you have what you are going to manufacture. After you manufacture it, it goes to stores.
In our last conversation with the ESRB, we were looking at a teen rating.
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I'd recommend you bookmark this site
http://www.halflife2.net to keep with the latest news.
Also keep tabs on this link in their forums where people sent email to Valve and their answers:
Valve Q&A .
It's up to page 44 now, but has alot of info from curious people.