The key is mostly in the...
The key is mostly in the underside of the base, and the shape of the casting. The first coating was porcelain, and later rislan or thick plastic. Modernica has a gritty base finish with a flat bottom. Knoll's are webbed inside the base and some had optional weights inside the webbing. The plywood is also a key to spotting them, but that is more experience to see a real diff.
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