German KSK has a version, the HK USP 45 Tactical I believe (P12). Otherwise, most that use the HK use the 9mm, usually in a USP variant.
That wouldnt surprise me, I was a liaison with the Norwegians at Khandahar in early 2002. They were using Glock 17s as sidearms but there was some weapon swapping...The Norwegians loaned me a nice MP5, their troops carried the G3. This was part of a Coalition Spec Ops task force, pre NATO.I saw a Mark 23 on the leg of a guy in Kabul airport back in 2013. I think that he was with the Norwegian troops heading out on patrol, but unmistakably a Mark23