Donald Qualls
Subscriber
Convex, unless you are on the other side of the lens.
Yes. First (brightest) reflection is small and upright, indicating a convex surface. Your lens is in its original position.
The other thing that can emphasize the blurry corners is if the 6x6 mask is missing. These cameras were originally 6x4.5, were switched to dual format, but a lot of examples of the 120N had only the 6x4.5 frame mask and people would just remove that to shoot 6x6. This results in opportunities for film scratching, a well as letting the film hold more curvature than it would with the mask in place.
If you like that look, you can probably just pull the mask out of your other Holga to get similar results.