Vacheron Corps of Engineers Chronograph

[CZHACK]

This post is in the American rather than the European forum because I am looking for US sorce information. I recently purchased Vacheron Constantine chronograph (#383986) made for the Corps of Engineers (#2182) in WWI and would appreciate any information on engravings on the back case or suggestions on sources of information. The second, third and fifth lines were engraved by VC and other lines in high quality script font later.

Douglas Sargent Blais
CORPS OF ENGINEERS
U.S.A.
Bordeaux France
No. 2182
U.S.A.C. Fred E Richards

Thanks for any help.

Mike