I'm using 84212218390-02 Hardware 2.0 and it works fine with my 4S on my 2011 with BMW Apps and it has a fan.
Hardware 1.0 doesn't have a fan and was discontinued.
A buddy of my mine just picked up a new 2012 M3 and he got hardware 2.0. His cradle would into recognize his phone in the iDrive. We plugged in my cradle which was identical down to the label and it worked perfectly every time. Needless to say he is getting a another cradle. You may be fine with hardware 2.0 or greater as long as you're lucky enough to get functioning cradle.
Best case scenario would be to buy the cradle at the dealer and test it on-site before you leave. There are a lot of rotten apple cradles out there.