Here is the WWI Model 1917 knife.
http://arms2armor.com/Knives/trench.htm

This is the 1918 Model Mark 1 and some varients that took it's place.
http://arms2armor.com/Knives/m1trench.htm

Originally Posted by godofthunder9010

If said Marine had the sheath custom made w/ Marine insignia added later, I'm not following how to conclude whether it is WW1 or WW2. Thanks so much for the information and response!!

Prior to 1918 enlisted Marines were only authorized wear of the Marine Corps emblem on their cover. Not on their blouses. When the Marine Corps was attached to the AEF, one of the conditions was that the Marines must trade their Forrest Green Uniforms for Army Kakhi's/OD's. This meant that they no longer wore the campaign cover or visored barracks cover but the Army fore and aft overseas cap. The emblem on the Piss cutter is much smaller and was not immediatly issued. Instead the Marine Brigade wore the US Army US disks on their blouses and covers until cover devices were procured after they landed in France. The first emblems issued were similar to the US disks in that the Eagle Globe and Anchor were stamped into a metal disk and not seperate and in relief.

The Trench knife in orginal issue came with a metal scabbard fitted with belt hangers similar to that of the Springfield Bayonet. During issue in WWII some knives were issued without the scabbard due to shortage's or storage destruction and the Marines were issued leather sheaths as a replacement.

The WWII Marines were also maniacs when it came to putting the EGA on everything they owned. And by the angle of the wings and eagles head it appears to be a WWII era Cover device.

Well I'd say that absolutely anc comepletely nails it down. Thanks for the info, my wife's Grandpa will probably find all of this to be very interesting. Sortof interesting that the Marine in question just sold his knife off and all. Wonder why? These sorts of items are always a heckuva lot more intersting when you know who had it and what they did with it, etc. This was several decades ago that it got bought then gifted and such, so there's no way of knowing.

Its a pretty cool combat knife. Do they issue anything like them anymore?

No, but there are companies still making knives like them.

That's interesting. It could be in WW1.

The one G of T showed is the second 1918 issue, the Mark 1. While they weren't issued in WWII, that doesn't mean they weren't used. Look at the Springfield `03 rifle, it was used even into Vietnam.

The one you show in the picture is a collector's item and, as in the site I posted earlier, there are fakes made and sold as antiques. But there are also reproductions not meant to deceive buyers.

They were issued to paratroopers until they started causing trouble with them. One such instance was when Colonel Sink's (of the 506th PIR) jeep driver, Lorraine, socked a German prisoner at Brecourt Manner.

Originally Posted by Missileer

The one G of T showed is the second 1918 issue, the Mark 1. While they weren't issued in WWII, that doesn't mean they weren't used. Look at the Springfield `03 rifle, it was used even into Vietnam.

The one you show in the picture is a collector's item and, as in the site I posted earlier, there are fakes made and sold as antiques. But there are also reproductions not meant to deceive buyers.

Undoubtedly Missileer. The reason I'm pretty sure this one is real is because it's been sitting around my wife's grandpa's basement for 30-40 years collecting dust. He's shown it to his grandkids a few times but pretty much knew nothing about it except for the following: His brother gave it to him and his brother bought it off a Marine.

Thanks so much to everyone for the info!! Probably a safe bet that a good number of skulls got busted by this guy.

no joke.