Fortunately, for the M-1917 we have pretty precise production figures and serials. Hatcher has a little chart of 1918 production in his "Notebook".
I would hate to have been the guy in charge of storage at Eddystone if they were on a 2-months-either-side basis. They were cranking out 4000 rifles a day, plus spares; that is almost 30,000 a week, 120,000 a month. Two months either way could include half a million rifles. I doubt they kept that many on hand; they were delivering rifles almost as fast as the Army wanted them...... and the Army's idea was to put 4 million men overseas ASAP.
"You there; sweep that floor! I've got half a million rifles to pile there!"
Eddystone production, once the tooling was set up for the changes from P-'14 to M-17, cranked out almost a million and a quarter rifles in about 16 months. That does compare rather well with 350,000 for Rock Island in its entire career. In some ways, it is the difference between getting paid for a job.... and getting paid for a job per unit actually manufactured.
My higher Eddystone M-1917 number is 1132###, so it is getting pretty close to the end. Still a decent shooter, too.