AEF 21st Engineers Uniform & Victory Medal

AEF 21st Engineers Uniform, ID Tag, & Victory Medal Enlisted issue M1912 olive drab wool service coat has "US / 21" and Engineer discs, Sergeant First Class of Engineers rank chevron, two overseas service chevrons, honorable discharge chevron, and a 1st Army Engineers shoulder insignia.  Left chest displays a US WWI Victory Medal with St. Mihiel and Defensive Sector clasps.  Interior is named "M Jackson" in purple laundry pen.  Complete with breeches. When this came to us it also includes an ID tag from "S.F. CAHILL / HQ DET / 21 ENGRS".  The collector who had this purchased it as an identified set, as there is a price tag in the pocket indicating that it is a set belonging to "Sgt. Cahill."  Research confirms that Sylvester F. Cahill hailed from the bay area of California, which is where the collection from which this uniform came was located.. but he was listed as a Private on the way out and back in the transport records, so clearly the uniform was not his.  The Victory Medal is plausible, as the 21st Engineers was eligible for St. Mihiel and Meuse Argonne, but was more than likely added to this coat.  I did not find a "M Jackson" in the transportation records that fit this rank, either, so my diagnosis of this set is original parts, assembled for display.  We have a few more research resources at our fingertips today than were available to the last person to own this material!  Sometimes that can lead to small disappointments, but it is always better to know than not, and in this case the components are at the very least all original.. just not original to each other.$50 - $100