Cards sometimes have full name, sometimes F.M. Köln (typically on early two-layer embossed cards) and sometimes F.M.K.
The embossed cards have a producer's logo on the lower left, ""DRPA, the A slightly smaller.
I don't know what the A is, but D.R.P. = Deutsches Reichspatent and will refer to the process used in embossing the cards.
The model in FMK 4865-4, Wally, appears in many Rotophot cards (see RPH logo). Manger became formally affiliated with Rotophot and then issued cards with a combined logo, see the final example card.