Ah hah. F. was not for a fella but for Wilhelm's wife Frieda Lustmann. I'm highly confident that it what the F stands for but this would seem most odd as typically one sees Witwe. She must have placed an order with a maker and he inadvertently applied her initial. Also the ampersand is absent. Seems the concern weathered the storm for at least 75 years.

Kind Regards,

Raimey
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