Cabinet design looks like Sylvania/GTE. That's where I recall seeing that type of front-edge treatment, with the routed slot on the sides and the beveled, deep front picture-frame.
There does appear to be an extra woofer, in any case.
Marantz foam grills were brown and I don't recall ever seeing any with a beveled front edge like that. The drivers don't look right for Marantz either for the period they used foam grills.
The warning tag on the back says “a design product of CEI” or something like that, not sure who that is but it might be a clue. There was a CEI that used to make tubes back in the day, maybe the same parent company?
Thanks everyone! there is a very faint circle with some writing on it on one of the back of the speakers that I can't make out. I thought originally Marantz. The Extra wolfer (puppy) will not stay away from the cicadas..