Fuel Injector Type A vs. B
 

I have a 2008 535xi Wagon and on a recent trip it went into 'limp mode'. The non-dealer mechanic we brought the car to said the fuel injectors needed to be replaced. I told him the dealership had replaced them in 2011 due to a recall on the High-Pressure Fuel Pump. He said that was unlikely because the injectors he took out of the car were stamped 'Type A' and that if they were changed out, they would have used 'Type B'-post recall parts. His belief is the recall work was never done or they used faulty 'Type A' parts. Can anyone add their technical understanding to this assessment?