Right. The 2010 product keys don't work in 2012. However, since you don't have to activate a network version, any successful installation of the software should work when pointed to the NLM server. You'll get a -5 or 0.0.0 error until your new .LIC is added, but it should work in theory. You probably should just wait for the 2012 seats to be purchased though. You can always deploy the software via GPO or similar afterwards.