I think a 1974 production Colt would have the narrow tenon front sight.
It doesn't matter. Front sight installation is not a common hand tool DIY, it requires some tooling and technique. I leave mine to the gunsmith.
As dahermit says, a cross-dovetail front sight will give you a stronger mount and more choices in sight type. It will cost more, though; and the front and rear must be of compatible heights to zero.