Mark,
After my experience with this two guns, I can say that before I sold them I was able to make some holsters out of them, and as far as I remember, the main differences between them “at list for our interest†is that the Python has a more slicker finish, like a dehorn work on it, and it seems to be a beat smaller on the frame, and at the trigger guard part and cylinder, also the vent rib on the Python and the front face of the barrel and under lug differs from the King Cobra, if detailed moulding is done it would fit tight if you start using the Python for a finished King Cobra holster and viceverce, also it wont make that particular click when you reholster the gun, my advise will be to buy a mold for each gun you are looking for, so you wont have those particular inconvenients , and your finished product will have that perfect fit each time, IMHO.
Hope my comments can be of help.