I think in this case the prints should specify the dimensions of the top-strap cut, locating pin-holes, and rear sight dimensions all in one document. Simplifying the process of converting their existing Elliason-type CAD drawing to match the specs of the Python. All they basically would do is duplicate their existing file and punch in the new specs and it run off a prototype.
I get it from the perspective of making it easier on Kensight. Basically, they want the Colt drawings, because it would simplify the process and make sure they can machine to the exact specified tolerances and dimensions. Reverse engineering only gets you close. Probably close enough, but maybe not...and you don't want to deal with a bunch of people bitching about how their sights don't fit right/zero/etc.
Y'all are killing me with the Python talk...