Actually, for the undead veiled status, the game does not make a distinction between varieties of equipment: any helmet will do for the helmet slot, etc. If undead had not been added so late in the development process it would have been better to add an extra flag to equipment to determine if it was visually concealing enough to count, but there wasn't enough time to do so.
Aesthetically, you may still want to go for cowls and other concealing armour (most are fine).
