Marion,
Thank you so much for the information!! I did go to the Sitrep reports as you suggested and found mention of Lt. Gustafson on 11 Jun-12 Jun 1944 @ 0355. As I read the entry my heart was in my throat. Thanks so much for directing me to this entry! It appears that Colonel Stanley, who was killed, was commanding the 1st Bn & was replaced by Col. J. B. Chubbuck 1st Bn. company C (sorta looks like an "O" instead of a "C" but doesn't fit). This would seem to indicate that Eugene was still in company "C" (or could he have been transferred back and forth between companies?).
According to Eugene's obituary: He arrived at Fort Belvoir abt 1st of Nov 1941 where he became a Corporal in Dec 1941; Commissioned 2nd Lieutenant 24 Jun 1942 at Fort Belvoir; was briefly at Camp Edwards, Fort Bragg & Camp Bradford (no dates given but perhaps between late June to early Oct 1942); He was Commissioned 1st Lieutenant at Camp Pickett about Oct 1942 and was Commissioned Captain shortly before the invasion of southern France in Aug 1944.
I'm still smiling over my question about Regiment C! Thanks for your answer!!
In appreciation,
Susanne Brown