Pvt Arno Schroeder is not listed as having been WIA while with the Sixth Marine Division according to that listing in the "History of the Sixth Marine Division".
I suggest you take the following action over the signature of Privte Arno Schneider:
You should write to:
National Personnel Records Center
Military Personnel Records- (Marines)
9700 Page Avenue
St. Louis, MO 63132-5100
Ask them for standard form SF-180. When you receive that form, fill it out
and return it to them. You will receive (in up to six months) your relative
's military records. This information is only available to next of kin.

You can also access a Standard Form 180 from the Records Center's web site,
which can be used to submit requests:

www.nara.gov/regional/mprsf180.html

Mr Dornan - thanks very much for your quick response!

I have a SF 180 "cooking" in the Pers Records Center - this was tried about 10 yrs ago and unfortunatly no records were found. The lame excuse was his records were destroyed in the 1973 fire - but no Marine records were affected by that fire! We're thinking the records have been mis-filed. Perhaps a congressional nudge will help them find something!

Does anyone know if Daily Logs or a Unit Journal of some sort is available for the combat years?

This is a great forum - thanks for your help!