Technical Flathead Fuel Pump Stands

I have these fuel pump stands and noticed that they are slightly different. One has a couple ribs at the top and the other smooth? Are all '32-48 the same, is one ealier than the other, or aftermarket? School me, please.

 

I believe there are two different heights for them.

 

Two different manifold mounting heights.
The one with the tube is early.

 

The fill tubes are within 1/4" of each other. Looking online, I see similar to the one w/o tube as '35-48. Does that make the one with the tube '32-34?

 

Maybe late 33 and 34.
32 and early 33 did not use a housing. The pumps bolted right on the manifolds.