Air Force pilots went through a formal Skyraider training class at Hurlburt Field, Florida (Eglin Air Force Aux 9). The earliest classes carried the designation "Express" followed by the sequential class number.
Back row:
Capt Charles C 'Vas' Vasiliadis, Capt E.H. Richmond, Capt B.D. Gregarios, Capt J.H. Winston, Capt Harland M. "Sonny" Davis, Jr. (KIA 72/07/07 F-4D)
Front row:
Capt Warthom J. George, Capt Donald S. Hynd, Capt Jerry P. Hawkins (KIA 65/03/21)
NP: Col E.J. Witzenberger
Possible years 1964-5
Source: Air Commando: Inside The Air Force Special Operations Command
by Philip D.Chinnery, pp. 176+
http://skyraider.org/skyassn/classpics/hurlphot.htm