By "going for," I assume you mean asking prices. Sellers often ask unrealistic prices.
Looking at the new photo, the watch looks totally legit to me, just with some condition issues (some dial damage, aggressively polished case). But a nice find, and great for $100. With a watch like this, double-signed watches don't usually add a lot of value, but you never know, someone might put more value on the Tiffany signature than I do.