Definitely looks like WW1 Thew reverse chevron's and buttons are both from that era.

Here's a good site, complete with photos kiddo!

http://www.ushist.com/wardrobe/us_wwi.htm

more...

http://www.frankscollection.com/military/wwi/

http://www.aefsupply.com/ww1.htm

http://www.schipperfabrik.com/

http://www.warscholar.com/WWI.html

Books

http://www.amazon.com/Uniforms-of-the-Grea...m/3K8ILZ3LTIU6E

Okay,

Heres the skivy on this particular jacket. This is a M-1912 Summer Dress Coat, Khaki. The unit displayed is the U.S. 55th Infantry Regiment, which was assigned to the U.S. 7th Infantry Division(Hourglass) during WWI. The U.S. 7th Infantry Division was formed at Camp Wheeler, Georgia(just south of Atlanta) in 1917 and, served in the Lorraine Campaign of 1918.

Regards,

Sgt. James Dunigan III

Able Co., U.S. 30th Infantry Regiment

U.S. 3rd Infantry Division(Reenacted)

Thanks Marne for the info!