I don’t have an M1918. If you’re thinking about the gun to the left in the cover, that is a Mark 1 Bren (although with a Mark 2 barrel), but yes there is an M1 Garand in there as well as the M1A1 Thompson.
The oldest gun in the photo is a Martini-Henry dating from the late 1800s, just to the left of the Garand, while the most modern that can be seen is probably the L85A1 further to the right.