I would bet half the farm that NO "reputable gun dealer" will know what he's looking at, other than a stainless steel Single Six. This particular example is just too obscure for your average dealer to be aware of. Many would lowball at standard Single Six prices and then charge the full collector price.Take it to a few reputable gun dealers.
The latest RENE price guide had the original KNR4 (non Liberty marked) came in at $615 NIB. Then the Liberty marked version (around 300 made, all with a 64- prefix) came in at $950 NIB.