[DUMBGRUNT]

Manufactured by Bell, UH-1N, the helicopter affectionately called "Huey," first entered service in 1970 to assist in search and rescue missions.

Maybe the N model came in 1970? I was in country '68,'60 and '70, rode in many of them?

[NorthMountain]

The November model is a twin-engine variant that did indeed enter service in 1970. The two or three I’ve seen recently did look a bit worn ...