So out of the last batch of M1918/40s, there were three of these very rare M1918 helmets. The difference being the full liner ring on the M1918s, and the 3/4 liner ring on the later M18/40s. Another difference is the more defined "swoop" of the ear protection.
These are extremely hard to find, and I can't get any more from my suppliers. Actual helmet is pictured. Will come with reversible camouflage cover.