Shure, Alemite and Excelsior built cabinets that could be ordered to attach on to one another to create long lines of Merchandisers.
You can see the squared off end on this Shure Work Station. The top and side was manufactured different, on these models, in order to allow this type of stacking.
I found this below image years ago of two Shures at a Brake Museum. I am unsure what state this display is in.
Excelsior and Alemite also built cabinets with this type of expansion in mind.
