Originally posted by Karl in NY:
A genuine 100% gun without original box is definitely way less collectible than the same gun with box, hence worth considerably less.
Gun/box "marriages" don't work with collectors, so I would not suggest you go looking for the "proper" box, even though counterfeit blank labels are available.
A 100% M39 "no dash", (as opposed to a 39-2) is much more of a collector item than a shooter, both because of far fewer numbers having been made, but also because the M39 no-dash had a fragile extractor and replacement extractors are virtually unobtanium.
If I were you, I would preserve the gun as unfired (assuming 100% means unfired, which in my opinion it does). I would also request a "factory letter" to establish the shipping history of the gun.
I realize you're new here, but give us a chance, and get to know the players. Welcome.