User blog comment:Hawki/Nova Covert Ops, part 3 - Reflections/@comment-72.197.211.140-20161201173638/@comment-58609-20161201221236

NCO is post-LotV though, so hypothetical pre-LotV intel is a moot point. So, within the scope of NCO itself, we know that the Defenders trigger the Tal'darim into attacking. We know the Dominion have some level of communication with the Daelaam, which conspicuously doesn't include the Tal'darim. The average citizen is probably going to see them as being just protoss (with understandable reason), but even before LotV, the Dominion knows the Tal'darim are a separate faction. That level of intel is only going to go up.

And Vardona is a core world, it's going to have defences regardless. If anything, the mission demonstrates this in that that a viable resistance can be mustered on the ground at all.