The "no drill and tap" mounts I've seen place the scope too high for proper cheek weld and natural handling of the gun.
I say if it's your gun, and you want to scope it, go right ahead. There are a number of decent mounts around. The classic looking one piece mounts look good on the 03's. Leupold (?), Redfield, and Bueler made one peice mounts for them. Most made for the A3 use the rear inverted dovetail sight base as a mount point, and the front two holes have to be drilled and tapped. Not sure of the rear is drilled and tapped.
I have two sporterized 03's. Besides sentimental value, I like them far more than original versions of the same gun. In original form, they are heavy clunkers, in sporterized form, they are fine, graceful, beautiful quick handling guns. Probably wouldnt choose to do it today, but already owning them, and them having been done when it was practical and relatively inexpensive, I have no regrets. They certainly have more character than anything made today.