I've found field grade SxS's to be exceedingly hard to sell. I collected NID's for many years and generally stayed away from 12 bores with a few exceptions. Some 4's and 5's and a 3 inch 12 bore on the 10 Magnum frame. (#500xxx) Your field 12 is a very fine gun and approaches benchmark status. The bulk of NID production were 12 gauge guns--so there's always plenty to choose from--although few as nice as yours condition wise. Most field grade guns were used hard. The later NON--indicator guns seem to sell better in my experience. Nicer looking frame/wood/checkering/dimensions seem to attract more interest. There are many more folks looking for Parkers--Foxes--Smiths. The Ithaca's always came in last as far as the number of willing buyers. You will most likely be disappointed in what you are offered at a gun show for your gun. I don't know what you have invested, but if its over $1000--be prepared to take a haircut! Enjoy your fine gun and put it to work in the field or at the traps! Strictly my impressions and opinions from 50 years of loving NID's!!
