The old style Colt's, like the Python, Diamondback, and even the inexpensive Official Police and Trooper lines had to be totally hand assembled.
At the factory, a Master fitter hand stoned the internal parts until they fit, then bent and adjusted the parts so they worked properly.
This ran the price up, which is why most of them were replaced in 1969 by the new Trooper Mark III, "J frame line.
This new line was the world's first "machine fitted" revolver. The parts were manufactured to very close tolerances using an early form of MIM (Metal Injection Molding). This early form of forcing a metallic slurry into a form then heating it until lit was fused into a solid mass, was known as "Sintered steel".
These new guns were assembled by standard skilled people by selecting a part from a bin and test fitting it. If the part didn't fit, another was tried until the part fit and functioned.
These new Colt's had actions totally different from the older Colt's and included a modern transfer-bar safety and ignition system.
The Trooper Mark III, "J" frame series was followed by the slightly improved Trooper Mark V series. In the mid-1980's, the Mark V was upgraded to stainless steel and fitted with a full lugged barrel and was the King Cobra "AA" frame.
The Python was different from even the older Colt's with the same "E&I" frame.
The Python was a totally hand fitted and polished model, and was intended from the start to be the finest DA revolver ever made.
The Python was a true semi-custom gun and a considerably longer amount of time was taken further adjusting and polishing the action to give it perfect operation and a smooth pull.
Among other features, the Python had a tapered bore to improve accuracy, for which the Python was famous.
Externally, the Python was polished to a far finer level than any other DA revolver.
The Colt Diamondback was simply a Python "look-alike" and was not finished or fitted to the same specs as the Super-Premium Python. The Diamondback received about the same level of finishing as the Detective Special, who's frame and action it shared.
So, the Trooper Mark III and Mark V were intended to be high quality mass produced revolvers and were a step above the competition in accuracy and external finish. The Mark III and Mark V blue job was possibly the best ever on a standard quality revolver.
The Diamondback is a well-finished look-alike, but doesn't have the smooth action, or the higher lever external finish, and did not have a tapered bore.
The Python was the finest finished DA revolver made, with an action tuned by experts to the highest level, and with the fantastic Python deep BLUE finish.
It was intended to be a Super-Premium revolver, and was built and priced accordingly.