[Steven Scharf]

Although Kelvar was invented in 1965, it was not used in personal armor until the 1980s. From Wiki:

Kevlar is a well-known component of personal armor such as combat helmets, ballistic face masks, and ballistic vests. The PASGT helmet and vest used by United States military forces since the 1980s . . .

So if a Veitnam era flak jacket, it was not Kevlar.

[Eagles6]

Well they would be even less "bulletproof" then wouldn't they? ;-)

Local surplus store had a bunch about 15-20 yrs ago. Either late 80s then or they weren't kevlar