Well not exactly in a retail sense, but you do make a point in technically. However with the latter being much more true.

That being said, note that if you go to a LBS that knows it's SS/FG vocabulary, and you ask for a "flip flop hub" they're most likely going to pull out a hub that's threaded specially for a freewheel on one side and for a cog/ lockring on the other. The same is also true for google/ many web stores when you search for it. So, you'll have to specially ask/ search for a fixed/ fixed hub if you want one.