Where did the German soldier (officer?) stereotypes of the monocle and
the dueling scar come from? Was there one guy in WW I or WW II who had them?

von Stromberg, movie actor and director. Sort of the prototype Jerry badguy.

v/r
Gordon
====(A+C====
USN SAR Aircrew

"Got anything on your radar, SENSO?"
"Nothing but my forehead, sir."