Excellent document on boresighting the P51 series and details on all 4 gunsights used and how to adjust each gunsight for center. By looking at the adjustment detail drawings it lends credence to crew cheif's making custom adjustments for their pilots.
Our P51's should have a cross on the backside of one of the props for center aligning the gunsights. N-3B, N-3C, N-9 and K-14. There should be an additional alignment mark on the back of one blade for aligning the N6 gun camera. But, Waffel still needs to put the projector lense in the N-3B of the F4U-1 and the reflector plate for the MkII in the Typhoon on the windscreen side of the gunsight instead of in front of it where the reticle really cannot reflect off of it......Latest generation of cockpits are the best so far though.
http://p51h.home.comcast.net/~p51h/sig/TO/01-60J-58.pdf
