Does a Trijicon SRO fit an RMR cut?

The SRO uses the Trijicon RMR footprint, so most slide cuts and adapter plates made for an RMR take an SRO. Most, not all — and the exceptions come from Trijicon itself. Its SRO product page states that mounting on a Glock MOS, Springfield OSP, Walther PDP, or H&K VP9 Optics Ready requires an SRO mounting kit, part AC32085. Those are four of the most common optics-ready pistols sold, so check before assuming a straight swap.

That qualifier is about the window, not the mount. The SRO has a much taller, rounder window than an RMR, and it sits further forward in the aperture. On a pistol with tall suppressor-height sights, a compensator, or a front sight that clears an RMR by a small margin, the SRO body can foul on it. The screws will still line up; the sight picture is what suffers.