i have a model 12-3 serial number 16dxxxx and i saw one for sale with the box serial number 12d and it had the one piece hinged box. would mine have the one piece hinged box or would the two piece box still have been used.
That's hard to say with certainty. They are both right at 82/83 and that is when they started to switch over to the one piece box.
I would guess if 12D was a one piece, 16D would have been to.