The definitive tuxedo shirt. Marcella (aka pique) front, collar, and cuffs. Turn-down collar. Three holes for
studs.
A turn-down collar is preferred for black tie as a wing collar would reveal the band of the bow tie. A proper wing collar should be detachable and laundered by a specialist, a hassle which few are willing to tolerate today.
A proper tuxedo shirt should only have three stud holes. While a stud set will have four studs, the fourth stud is a spare. Shirts with four stud holes perhaps were made without awareness of this convention.