Jd, the mount James is referring to fits the gen 1 models that have the rear sight attached to the cover plate, it won't fit the new xl where the rear sights separate. Unfortunately the Trijicon won't fit without an adapter and not finding any for the new improved site plate. The sig xl uses Romeo Zero and RMSc Optics. Sorry but hope this helps.

Josh T. Is correct in his findings. It won't work with the new Sig XL.
Sorry but given some time, I'm sure they'll be an option for what you're asking.

Hi JD, The Trijicon RMRcc Mount, Fits Sig Sauer P365XL, the Black adapter plate mounts directly to the pistol using Sig Sauer supplied fasteners. The Trijicon RMR®cc is then mounted to this adapter using the Trijicon supplied fasteners. Cheers and stay safe!