In the knife fight at the end, Mandrake gets cut on both cheeks but in the final scene the skin on his cheeks look very smooth with no evidence of scarring.
The knife dealer says the Applegate-Fairbairn knife is used by British commandos. Actually the knife is a redesign of the Fairbairn-Sykes fighting knife that was widely used in WWII, the Applegate-Fairbairn wasn't issued to any armed forces to this day.