No, it will likely get a spec bump at least. It just hasn't sold out
It makes sense for the 27. They will start the retina move with the desktop the biz types are more likely to buy since they are the ones typically with the cash etc. some of those businesses might be the same oct to sept fiscal calendar as Apple so they are buying now to use up budget money so it's not pulled as unneeded. Plus that model could be used by some tv productions and season filming did just start up in this last month. Plenty of new shows with fat budgets etc. So the 27 has had more sales and if it is about to be revamped production on the old one is stopped.
The college and high school kids are more about iPads and notebooks right now. Thus the 21's slower sales at this moment