The part to mount the beam rifle has movable grips, with hinge to secure the rifle to it.
This swing-type pelvis joint is quite an 'old' design already. XD Used since Gundam Ver. OYW, and has been implemented for HGUC Zaku II FZ as well.
A bit of reference to Sazabi's rear skirt armor can be seen on the interior details of Sinanju's.
This kind of movement is impossible for Sazabi though. It was held back by its Mega Particle Cannon placed in its abdomen.
7 days till its official release.
Images from Gunpla Secret Base.
