Vietnam

MACV-SOG officially began on January 24, 1964, under MACV/JCS structures. But many earlier missions were CIA-controlled predecessor programs, later transferred or folded into military channels through Operation SWITCHBACK. So historians looking for “MACV-SOG” often start after the period you are talking about.

Why so little is known:

• It was designed for deniability. Operations into Laos, Cambodia, and North Vietnam carried major diplomatic risk because those areas were officially outside the acknowledged U.S. ground war.
• The records are scattered under different names. Early activity may appear as CIA paramilitary programs, CIDG, SWITCHBACK, OPLAN 34A predecessors, agent operations, border surveillance, or Special Forces advisory activity, rather than “SOG.”
• The CIA-to-military transfer blurred the trail. State Department records explicitly describe the decision to transfer training of paramilitary groups, including Montagnards, from CIA to the Army as “Operation Switchback.” See FRUS, 1963.
• The archival record is thin. The National Archives notes that “few records of MACV-SOG are available to researchers” and that many reports likely remained with JCS rather than in normal archival holdings. See NARA Reference Information Paper 90.
• Participants stayed silent. Men who were ordered not to talk generally did not talk. By the time partial declassification occurred, many were gone, unwilling to revisit it, or still unsure what they could legally say.
• Later SOG overshadowed the earlier CIA period. The public story is dominated by 1965-72 recon teams, Shining Brass, Prairie Fire, Daniel Boone/Salem House, and Medal of Honor narratives. The earlier CIA-run or CIA-directed phase was smaller, more compartmented, and less institutionally “owned” by Army historians.

USASOC’s history also notes that early SF in Vietnam was very different from the later 5th SFG/SOG picture, and that CIA controlled the CIDG program before it shifted to MACV/Army channels. See ARSOF History, “A Team Effort”.

So the short answer is: it is little known because it was covert, politically sensitive, poorly labeled in the records, split between CIA and military archives, and later buried under the better-documented MACV-SOG story. Your memory may be exactly from the part of the war the paper trail was built to hide.