I don't know where the Swedish K's came from, but there seemed to be a lot of them around and the people who had them really liked them. I often wondered if, like the Uzi, they were really a good weapon or people just liked them because they were sexy - the spook factor.
The HP was kind of like the 1911 in that it was tough to conceal, but reassuring in the hand. In fact, I don't remember anyone who actually carried one and I'm sure they warmed many a desk drawer.
My friend of a friend one time related a story about an "embassy" office that sent all of their people to the range at TSN to qualify. Most were "retired" field personnel and round-eye wives/secretaries. They showed up with an assortment of weapons, most of which had never been fired or even cleaned. The armorer/rangemaster just rolled his eyes, made sure they kept them pointed mostly downrange and handed out ammo.
The Swedish K's were brought into Viet Nam by the Agency.