Thanks Brian, I'm in agreement with Andrew, the S/N would be 81404.
The question regarding position of the date stamp was a bit leadingup until 1918, the date stamp was between 1/8 and 1/4 of an inch below the Shield.
From 1918 it moved up to the base of the shield and the point of the shield was in line with the middle digits.
This positioning gives us an idea on whether it is a replacement receiver or not.
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