Other bits I could notice...
No safety location dot on slide or on frame
Upgrade ambi decock with hex head fastener
Upgraded magazine release button
Trigger over-travel stop
Re-contoured hammer
No hole on bottom of MSH
Also says "9mm CTG" on barrel over chamber. Of all my 1-2 Gens, only my 60's era 39 no-dash says that. All my others say "9mm Parabellum."
Also, the front sight is dovetailed and there appears to be no separate barrel bushing which would be consistent with a transitional slide, but I have no adjustable sight 2-3 Gens to judge the look and shape of that front sight. Honestly, it kind of looks like a Model 52 front sight, but those were a part of a 52 slide, not a separate part you could tap in to a dovetail.
I find this one quite interesting.