I have on Latex Gloves and a Particulate Mask every time I 'visit' the KCA Forum.
Lots of old cosmoline here and you never know what that could be harboring!

FWIW - I don't think you can know for sure, exactly, what month a U.S. Krag was assembled.
It is normally a best guess arrived at circumstantially and by calculation.
(Other variables can always disrupt smooth manufacturing, processing, and numeric order).

I have two model 1899 carbines, numbered 725 digits apart. According to Poyer's tables, one was made in September, 1901, and the other in October, 1901.
Bill Mook's figures seem to put both in October, 1901.

I have two model 1898 rifles, whose serial numbers are 2,143 digits apart. Both Mook's and Poyer's calculations place manufacture in July, 1901.

I'm happy and content to have an approximation and context of when something was made. I'm not looking for consecutive serial numbers.  :)