You may be correct about the SW1911 Novak working on some 3rd Gens.
My 3913 rear low-mount sight is metal, has 'Novak' marked on it, and a set screw to lock down.
However, my CS9 has a plastic rear 'Novak-style' sight that was apparently carried over from the S&W Value line 900 series. My understanding is that it slightly different so S&W wouldn't have to pay Novak a premium.
I would think a sight specialist like Novak or Dawson and a few measurements could help clarify exactly what dovetail you have and IF or what RDS mount would work.
Any info or a cross-reference of 3rd gen dovetail measurements could help many of us in the future, as optics on pistols are likely to become as prolific as scopes on rifles. I vaguely recall seeing a chart with dovetail angles & measurements posted somewhere??