Um, I'm sorry but that isn't parsing for me. Serial numbers aren't "calender" or "fiscal" year; they're just a stream from 1 to the end. How those line up with the FY or CY is purely coincidental. Some researchers are attempting to "pin" serial ranges to years but it's an art more than a science and the end result will never be correct. It won't be correct as the guns weren't finished in serial number order. The "range" of "out of order" could get quite extensive.
So serials aren't pinned to years in any meaningful way.
Cheers.