Shutter Guard on Early Automat?

[Nicky]

I was lucky enough to purchase an RF 111A (SN 614172) in very good condition recently. I noticed that the Italian Rollei website have split the serial numbers on this model 568516- 610645 Aug 1937- Feb 1938 (K4-630) and 610646- 804999 Feb 1938- March 1939 (K4-631). I guess that would date mine to early 1938. Similarly, my camera has a shutter guard. Was the shutter guard the only difference between them for this model?