Seeing the round gripped LanCay M9-XM on ebay last week made me realize that I don't think the other variation has ever been featured here. When LanCay made the solid tang bayonets they produced the standard round grip (as seen in the auction) and a corresponding number of bayonets with green M7 style grips. Here are front and back views of the bayonets
Here are pictures of the blade markings on the two different variations; USMC and US Army
Nice pictures!
Strange enough, not only there is a visible difference in the scabbard configuration between the USMC and US Army versions, but note also the hyphen on Lan-Cay in the Army version.
There is not many information about these LanCays full tang.
The Brett book shows two of them, both with USMC markings.
Few notes ara available on the Frank Trzaska website.
Here http://www.usmilitaryknives.com/knife_knotes_2.htm (bottom page)
here http://www.oregonknifeclub.org/frank3.html (middle page with picture by Cole)
and here http://www.usmilitaryknives.com/knife_knotes_5.htm (in the middle, with picture of one USMC version).
These bayonets were manufactured in pairs and submitted to the USMC and US Army that way. Twenty pairs to the USMC and ten pairs to the Army. A pair consisted of a solid tang bayonet with a standard style round grip and one with the two-piece M7 style grip. Both styles have a welded pommel but the round gripped model has some interesting features to overcome the problems faced by not being able to remove the pommel or grip.
I have two complete sets in my collection, USMC and US Army. When time permits I'll post some photos of the round gripped features.