Peter
This airframe was also marked at one time, as MX-19
Seems closer on timeline to 1972 (your photo)
https://www.helis.com/database/cn/11436/
1970-02-25 BV-107M, c/n 2583 , ff?
accepted BuWepsRep, FR, Morton, PA as CH-46F 157684 25Feb70
xfer HMX-1 06Mar70
(1979-07-01) Crewed her as HMX-1 /MX-19 from early 1980 until I left for KBay in 1981
(1987-00-00) assign HMX-1, I crewed 157684 when she was still an "E" and
Converted to CH-46E(SRM) approx 1988
noted HMX-1, MX-22, Sep96
w/o-crashed & destroyed by fire in Orlando, FL during Presidential support flight, 4 crew unharmed, 06Sep96. HMX-1