Where can I find a 3rd generation box for a 1076? What do they look like? Any pictures please

I’m not sure if this is what you mean, but I just bought one of these for mine.

Category - Handgun Cases

Fits great, got it in 2 days.

JSS

Third generation boxes range from the earlier one piece cardboard box to the recent plastic box. I would think any plastic S&W factory box would work as far as making your 1076 complete with box.
You could check Gunbroker and the other auction sites.
Midway has them also.
Smith & Wesson Polymer Gun Box Up to 6" Barrels - MidwayUSA
The one from Midway looks like it will pass for the 1076 era.

The boxed 1076s I have seen came in the one piece folded cardboard box like this one.


Hopefully you can find one in better condition...