So apparently there was a change. I don't know when it was issued, but it's awesome.

Now, not only are all of the extras from my free copy of the "Valve Complete Pack" giftable... but I have an extra copy of Portal 2 giftable. Kinda almost sad now that I already purchased two copies (one for my wife). So even though I have most of the Valve games, now I have lots of extra copies of various games. I also have a few extras from the Potato Sack that I'd already bought.