This is a good question. I looked at another question slightly further down the list concerning the same issue, with the community manager answering with:
"While DS3 is "grayed out" in your Origin client, you will be entitled for DS1 with the release of DS3. The game will not shown "grayed out" like DS3, because DS1 is available at the Origin store, but this pre-order bundle will give you DS1 not before launch of DS3."
I also point out the reply given by that questions original asker stating that the DS3 purchase page says, and I quote
"DEAD SPACE 1 DIGITAL DOWNLOAD CODE WILL BE PROVIDED AT TIME OF PURCHASE"
So yeah. Told one thing at time of purchase and then told we won't get access to it until DS3's release.
Smells like bad customer service to me.