That depends on whether you're collecting any Pythons, or JUST true factory Pythons.
Colt never released any of the reported TWO .41 Magnum Pythons they actually made.
These guns were made up for a distributor, but Colt quickly decided the Python simply wasn't up to the .41 Magnum and both guns were withdrawn and are now in the Colt museum.
All the .41's floating around were made up by custom gunsmiths, and are NOT factory guns. They're dangerous fakes.
The trouble is in determining whether a non-standard Python was made that way by the factory, or was altered outside the factory by a custom gunsmith.
The ONLY way to ever really be sure is to buy a Colt Historical Letter which details in what form the gun left the plant, and lists any custom features.
A good guide line is, if the gun is in any caliber other than .357 or .38 Special, it's a fake.
If it has really radical changes, it's almost certainly a fake.
Most Colt factory Custom Pythons are engraved and embellished, have fancy wood grips, are some type of commemorative, or special finishes.
If you want to collect true factory Pythons, it's going to be a big and expensive job.
In addition to the known versions, there are the private edition guns Colt made up for fraternal organizations, private clubs, and for individuals willing to buy at least 25 guns.
Since these were private editions, only Colt and the buyer even know they exist.
If you intend to collect "one each" of custom non-factory Pythons, you have a totally impossible job.