I owned one in decent condition, gold plated base metal, with the Valjoux 72C (day/date/month model), which seems to be more common. I hardly ever see the type you show for sale. Double check that it's "steel" and not just "steel back" as that makes a big difference in price. Contrasting colors on the subregisters adds more value. All I can say is check ebay past sales, because NOS 45-year-old watches don't come up that often. The day/date/month version with the 72C movement in like new condition (with box and paper) sold for $2,200 recently. I would expect this watch to be significantly less.