I understand what bluez is saying, but in this particular case it could not be further from the truth. THAT IS NO NOVELTY. You have a truly rare collector piece. One of only 251 made. There is a premium for the nickel finish and also for having the original box and paperwork. Anybody that tells you that your gun isn't worth any more than a .357 model, they have no idea what they are talking about. There are a lot of Colt collectors that would give their right arm for that gun. Do not shoot it! Contact Colt and get a history letter on that gun to include in your original box as verification.
As to value, it's hard to say because all Pythons are bringing crazy money. As a ballpark, Blue Book says $1600 for the gun, add 50% for nickel finish so that's an additional $800, plus another $100 or so for the original box and paperwork. So you're looking at essentially $2500 to the right collector. Then add another 20% if its unfired.
Sorry bluez, but I'm a Python collector and I keep up with these things. A $1000 Python these days would be a well-worn sbooter with no box.