Is all that on the box? I would depend on what caliber(s) it fit. I've been interested in this stuff for 20 years, and don't think I've ever seen one for sale, let alone actually sell.
It worked by putting the thing in the barrel, putting the target on the wall holding the muzzle close enough to the target so that when the firing pin hit the rod it was driven out to make a dot on the target. The system I've heard of was in fact called the Hollifield Dotter.
No idea what value would be. I'll send you $200 cash in the morning, if you'll take it. Adding a zero to that offer might not be enough. Try posting on the military trainer forum. Somebody there might be able to help.
Marrage doesn't just happen, you have to get out there and expose yourself to it, you know, like chicken pox.