The illustrious .22 suppressed Hi-Standard HD, has seen use since the OSS days of WWII. These guns are usually based on the older models A, B, D and E.
Less common, is to see a suppressed model based on the model 107 Military.
I came across the pictures below on Falfiles a while ago. The poster made no claim to the weapon, and didn’t know anything about it.
The serial number range dates the gun to be a built between 1968 and 1972. Is it still considered an OSS gun? OSS turned into the CIA in 1947…
From the looks of it, it has seen some use. Perhaps in S.E. Asia?