^ Yup, that's what I thought. :)
Here are two more options of how a Boxer-based mobile gun system could look. Both are based on the French GIAT/Nexter Vextra design, which was trialled, but ultimately not adopted. Too bad, as it's a cool-looking beast.
Vextra 105 with a 105mm gun turret (as on the AMX-10RC)
SOURCEVextra trials vehicle for a reduced-recoil 120mm gun (120 FER (Faible Effet de Recul) L/52) in a lightweight turret called 120 POLE (POrteur LEger).
SOURCEThe well-sloped glacis kinda reminded me of the Boxer. Looks like you could easily cut-up a Leo 2 turret to get something similar to the turret in the second pic.