From their statement, it does sound like there will be a post-release demo, which is fine.
Quite. In fact, I VASTLY prefer post-release demos to pre-release demos. A post-release demo is more likely to be indicative of the final code, rather than the state the game was in a few months before release (and hence lacking those last few months of serious polish).
I want game demos to actually be representative of the retail game; not some kind of 'beta' preview.