Kestryll
It appears to be a Novak style cut on the slide - which requires machining a flat and a larger dovetail, so you'd have to get a smith to do it.
Speaking of the sights:
Are the new rear sights actually a real "Novak" dovetail cut? ...allowing interchangeability with aftermarket sights... Or are they just a "lookalike" with a different cut?
Inquiring minds want to know...