A V-12 can have perfect primary and secondary order harmonics if it uses 120° crank throws and the bank angle is in even increments of 60°; 0°, 60°, 120°, or 180°. So 65° isn't perfect but Ferrari began experimenting with bank angles in their F1 cars in the 1950s (Ferrari, you might have noticed, doesn't spend money to advertise, they spend money to race and the racing is their only deliberate advertising).
They found the 65° bank angle gave them more flexibility with respect to carburetors and distributors and other stuff that normally lives within the 'V' without wrecking the engine's harmonics. IIRC the 1967 V-6 Dinos were first street cars with a 65° bank angle and the 1992 465 GT was the first 65° V-12. I guess nobody complained so they've stuck with them.
On a similar note, the 512 Berlinetta Boxer didn't have a boxer engine. It was a 180° V with only six crank journals. A boxer would have had 12 journals. Apparently the guys in Ferrari marketing just liked the alliteration of "Berlinetta Boxer."
RE: the 465, my meaning was it was the first road car with a 65° V, not the first of all V-12s.
engine bank angles bkmk