Below are two photos of 174th UH-1C "pre-teeth" Shark gunships.
This second photo is the only picture your friendly webmaster has ever seen with the 174 unit number painted on the pilots doors of a Shark. Later only the Dolphins (slicks) had the unit numbers on the doors, and they were always black. This is the only picture I've ever seen with yellow 174 door paint. I guess the unit was experimenting with paint schemes for the guns. Although it's difficult to tell in this scanned image, the Sharks already had the white "fin" painted on the top of the vertical stabilizer (near the tail rotor), and the white square was painted on the roof between the pilots green-houses. (Photo by Mike Bovre, Lane AHP, 1966)