I do not have any information regarding "Wound Chevrons" In all probabilty his records may have been consumed in the 1973 fire. Since you are not a direct descendant, it would be highly unlikely for you to obtain the records if they existed However, since you have his Division, Regiment, and Company, posting them here along with his name and rank could allow someone to determine where he was fighting. The date of his gassing would also help in pinpointing the village where he could have been injured.
Since you ARE in France go to the Meuse-Argonne Monument at Montfalcon near the Romagne Meuse-Argonne Cemetery. There you will find a map showing where all of the divisions in the M-A battle fought. That information is alo printed in "American Armies and Battlefields in Europe" published by The Center of Military History, US Army (latest printing 2002) available from US Govt Printing Office (Online) A copy of it is probably available for review at any of the US Military WW-I Cemetaries. Good luck