What deerslayer said... The last one that sold on Gunbroker was unfired apparently, not in the box and went for 480 plus 20 shipping. I have no idea what the box would be worth, to a collector in good condition it might bring 150 or more into the equation. The one you're looking at has an early serial # so it has the largest chambers, equivalent to the originals and is generally in the era of the "best" production years which is to say much better than any of the other replicas.
Here's a link to the Centaure fanatics associates... http://www.1960nma.org/
Check the piece carefully to be certain it is an Army model and not the Civilian model. The Civilians are exceedingly rare and in the condition you describe would probably be quite valuable.
I have my own in route as we speak, also in the box.