Pulled injectors (stock motor) yesterday on my ITR (120k miles) and all of them have some black gunk on the outer surface of the nozzle. Is this normal ?

 

After 120K, I'd say that's normal. Use mineral spirits if you want to clean it off, just be careful not to hit the pintle at all. After 170K, my injectors still flowed within 3% richest to leanest. You should be fine.