You too can also contact NARA, as they do have WWI records in the archives too. But please note, the fire that occured at the archives affected many of the records on file there:
On July 12, 1973, a disastrous fire at NPRC (MPR) destroyed approximately 16-18 million Official Military Personnel Files. The affected record collections are described below.
Branch Personnel and Period Affected Estimated Loss
Army Personnel discharged November 1, 1912, to January 1, 1960 80%
Air Force Personnel discharged, September 25, 1947, to January 1, 1964
(with names alphabetically after Hubbard, James E.) 75%
No duplicate copies of the records that were destroyed in the fire were maintained, nor was a microfilm copy ever produced. There were no indexes created prior to the fire. In addition, millions of documents had been lent to the Department of Veterans Affairs before the fire occurred. Therefore, a complete listing of the records that were lost is not available. Nevertheless, NPRC (MPR) uses many alternate sources in its efforts to reconstruct basic service information to respond to requests.
http://www.archives.gov/st-louis/military-...blic/index.html
Proud Daughter of Walter (Monday) Poniedzialek
540th Engineer Combat Regiment, 2833rd Bn, H&S Co, 4th Platoon
There's "No Bridge Too Far"