334A Bell Box vs. 333B wall set

[poplar1]

The hinges and cover screw can be mounted on either side of the chassis used to make either a 334A Bell Box (subset) or 333B wall set.
This is because the gongs are at the top for a wall phone, but at the bottom for the bell box.
The earlier wood subsets, such as the 295A, had the gongs at the top, like the 293A wall set.
So, what was the reason for the insconsistent placement of the ringer?

[Sargeguy]

I am not sure but there is a difference in the shape of the slots for the bells, so that both would open in the same direction despite the orientation of the bells.