"Check it out, it's not a Trooper with a Python Barrel"?????
That's exactly what it looks like.
I seem to remember that the Texas Dept of Public Safety once issued old Model Troopers.
So, my best guess is, some yob just HAD to have a 3" Python, and switched out the Trooper barrel with a 3" (probably one of the batch sold by Gun Parts), and THIS yob is trying to flog it on Gunbroker as something rare or unusual.
This COULD have been done better. Back in the late 60's early 70's, the Vietnam war was still on and new Colt Python's were just unavailable. So, several enterprising gunsmith's were taking still very available, recently discontinued Trooper models, and fitting Python barrels to the frame.
To do a "Troop-On", the frame was heli-arc welded up on the front of the top strap to match the barrel. A Python barrel was fitted, the action was tuned and the metal was re-blued to Python standards.
In 1969?? one of the gun mags did a story about one 'smith's process, and apparently the conversions really took off, with a fairly large number of people having it done.
There are more than a few of these out there, so before buying a "rare, early Python" check the serial numbers for proper Python serial ranges. In most cases, the weld is faintly visible on the top strap.
The only difference I see here, is the "do-er" didn't even take the time to get it right.