M1917 bayonet markings question

Hello folks,

I've been researching bayonets for the US Model 1917 and have encountered differing opinions on what the markings mean. Some people say the number beneath the eagle's head stamp is the date of manufacture of the bayonet, others say it's the mark of the individual inspector in the same fashion as the rifles themselves. Can anyone clear this up for me? If possible, please cite sources.

Thanks,

David

According to Gary Cunningham's 'Bayonet Points': "The Ordnance Department adopted the eagle head over number mark in 1917 so that the individual inspectors could be made responsible for their work", a great bayonet reference you can Google. Cheers, Don