Yes, it's enough to give anyone a headache. To muddy the waters further I read a theory somewhere that the company name on the distinctive oval brass badge (Standard Sewing Equipment Corp) was the name of a distributor, not the name of the company that actually manufactured the machine.
I was in the old part of Wabasha, Minnesota a couple of months ago and saw an old Gambles store front. The store was of course closed but the logo sign was still up on the store front. It took me back a few years.