The big GPU fiasco with the early 2011 MBP machines. Some of those defective GPUs also got into some late 2011 machines and a small handful of mid 2012 machines. (Literally all their current flagship machines no less!) Is there a way to identify the defective chips by inspection of the logic board? Do they have unique and known part numbers, or batch/lot numbers? I'm looking to identify suspect logic boards in the mid 2012 machines.