Is it documented exactly which i7 is in the mac mini late 2012?
There's no public Apple document that has this info. But, with a little bit of info from Intels' CPU specs site, you can assume that's the one.

There are sites which show you that info also (to see if your assumption was good):

http://en.wikipedia.org/wiki/Mac_Mini#Specifications_3

http://www.everymac.com/systems/apple/mac_mini/index-macmini.html

According to the EveryMac site, the 2012 Mac Mini use the following chips:


2.5 GHz Core i5 (I5-3210M)
2.3 GHz Core i7 (I7-3615QM)
2.6 GHz Core i7 (I7-3720QM)