You can email the photos to me.

Here in NZ at least (late?) 120Ys and B310/Sunnys came with the later model 56A 'box. I've gone through a few different boxes on my racecar. The main areas of difference between later type vs early 1200 56A respectively:
Gears are approx 12mm wide vs 10mm. (Really obvious when you put the two layshafts next to each other)
Bearings differ most notably needle bearing at front of layshaft instead of roller. (and layshaft diamtre there is fatter)
Cases are different when you see them next to each other notably:
- the lump in the tailhousing where reverse gear sits (early type is stepped - late type is just a round lump).
- Clutch cable hole is larger on the later 'box.
Shift feels unchanged (ie excellent, especially vs most other 'boxes of the period)

haha fandastick your not wrong
i was driving my old mans gtr torana and i hated it the motor doesnt really rev past 4500 and the gearbox is that nasty it isnt funny soo much rougher then my little 1000 box and im sure the bigger 56a's and 60 series would be a better box the the 1000 one

Yes, that's the 56A. It is a stronger version of B110s 56L.

Seeing is believing

Wow.

That would be a cool thing to have for the novelty of it.

How very strange.

i also know of a gearbox just like this, anyone know how/if they differ from a normal (late or early) 56a?? hmmm should i try to aquire it

Wow that is a blow out. Wheres dodgeman ? he could quite possibly tell us the origins of this mystery 56A smooth case.

Well now I'm confused. On the outside at least this is different to what I know/knew as the late model 56A. Very much like 60A based on the photos. Maybe it's from a really late model 1200 Ute or Van?

Would be interesting to see how it's different inside - seems unlikely Nissan would go to the trouble of creating a new casing without some more meaningful change/improvements.

I'm pretty sure I saw a smooth case gear box, but with 56 stamped on the side in an A12 B310 (in Oz)