How did the factory attach the housing ends?

Can you post a picture of where you are referring to? On my 8 3/4 the welds are not only visible, but surprisingly sloppy from the factory
housing-ends.jpg
These are how the housing ends should look, the chamfered edge would butt up against the housing tube and then be welded on at that point
At the risk of oversimplifying, the rest of the housing is only 1 piece
These rear ends are not like a Dana style rear where you have a large cast center section where you press axle tubes into them