Without photos, the words "rust" and "some wear" automatically push this to the bottom end of the price spectrum for me. Maybe photos would undercut the mental image I have, but maybe not.
If the box is original, the fact that you have a rare gun in its box probably starts the valuation at around $400 even in poor condition; the price would slowly climb from there as the determined condition improves. Maybe there is a collector out there who would go over $1000 for one of these in semi-rough condition, but I don't know. Most collectors will look for high condition guns, and those would be the ones that trade hands in the $2000-3000 range. Shooter grade revolvers would be stuck below a thousand in my guess (and "guess" is definitely the word).
So without photos, and leaving some room for grading, I would estimate from $400-800 for the gun I see in my mind based on your description.