The aerospace company had a background report on Merrill that showed no personal history prior to the mid 1940s. Given that the company does work for the U.S. government, it would not have hired Merrill as an executive before a full background check was complete.
It is revealed early on that Harlan Merrill (Lt Phillip Kuyper) mentioned to Emery Fillmore that he had been in East Germany (which didn't exist until AFTER the war) but that he fought (and was presumably killed) in the Battle of the Bulge which was fought at the Ardennes forest in eastern Belgium. The Allied Army fought from the west - it would be very unusual for an Allied Lieutenant already that far into eastern Germany to have fought in that battle.