Don't have to worry about it IF the prop hub drive lugs are threaded. On my VW engine prop hub that don't have drive lugs, I used all metal high temp locking nut and safety wired the head of the prop bolts. There again I use a red paint mark on the nut and bolt to check for rotation of the nut in the pre-flight. Never have had any movement. With the wood prop I check the prop bolts torque about 4 times a year.