I still consistently see NID's selling for less than Nitro Specials. Graded NID's would be an even better value had Nitros been made in larger numbers, in some graded form. That would even further depress the NID value. Now I can understand the late Nitros, with special features, bring more than the regular Nitros but when I see a beater Nitro listed for $600.00 and a NID right along with it in the same or better condition for $400.00, I have to shake my head. Then I have stop try to see if I can afford to pass on the NID.
I think part of it is that Ithaca doubles are hard for many sellers to figure out which model they have. A Nitro Special is easy to find in a price guide, but a Ithaca NID and Flues seems to almost always get lumped together and the older Flues does decrease the value of the NID. The Lefever name still hold a lot of interest even to this day. We know that the Lefever and Nitro are not even remotely connected except by a marketing under his name. Just like the Fox model B and AH Fox are two vastly different guns. Names do count in marketing.
I have several NIDs in the project rack in the gun room. Maybe someday I will get around to using a few of them on a upgrade project. They have decent lines and are a trim receiver that should lend itself to any number of enhancements.