Correct - MB was endorsing Fogs at the time. Reputed/alleged MB had a few "stiff ones" for breakkie, to see him through the day!
I'm unsure now whether it was the Piston Porter or Turbine Porter. Vaguely recall seeing a photo of a legless Piston Porter in Jim Sinclair's book, so it may have been the Piston Porter. I know it only flew a total 39 hours with Talair.