Visiting from 7 until 9th of April was
USMC UC-35D 166714
Expected from 12 until 14th of April
USMC UC-35D 166767.
Furthermore April 11th, State of Kuwait A340 from 20:25 until 21:10
Still there this evening, 17 May 2021. As Bram's photo already showed, the serial has been (re-)applied as "16-6714"; done by an air force painter? It was "166714" at least a few years ago, as one would expect.
Sorry 'bout that, I thought the question mark would explain enough... But it seems this UC-35 did a round trip to Amman today. No telling if or when it will visit DUS so it seems.