Op, I hope my post #12 helps. I agree very 1990's. Maybe early-mid 2000's.
I've done a lot of horse trading on boxes and one thing I've noticed is that the cman industrial boxes are few and far between on the modern day used market. Not just in my area but the general confusion on them seems multi generational and nationwide. If you strike out on the suggestions I have above you may consider pulling all the drawers and looking for a label on the inside of the "cage" part of the box.
But even if you find out what they are it ain't really gonna help in locating others. They seem rare no matter where you go.
On a side note.,,
Maybe someday I will be smart enough to not know anything about the gauge of steel on a a box dolly, the weld patterns, the caster brand--series--or load rating, the framework, overall build quality, current condition, specific require ments, uses, needs, etc, etc, etc...in order to criticize another mans needs and uses. Maybe. Is that a dig at someone? Probably.