The impact of this is probably pretty small...
Of that 4000, likely only a couple hundred would be Terrains and another couple hundred Equinox's, and those are relatively small numbers in relation to what the factories actually produce. Plus, this is something that GM would have known a fairly long time in advance, so they could easily work those numbers into regular production. Even if, say, 1 in every 8 are Terrains/Noxes (500), spread that across a several hundred dealerships in North America, and that's maybe 1 or 2 fewer delivered to an individual dealer. And, consider that these are built, ready, and already in Vancouver. These would have been delivered weeks ago, therefore built in the latter half of 09. Maybe had an impact, but likely not huge.
The good news is, I'm sure there will be some smokin deals on the west coast in March!