Below is an excerpt from my records of Savage Model 99 ages:
C= 1951: 5842XX(23C), 611xxx, 6117xx(24C), 6136xx, 6162xx(14C), 6222xx(24C),
D= 1952: 621686(3D), 625775(19D). 638145(3D), 643122, 655689(19?), 6693xx, 6726xx, 673018(27D)
Note that the serial number of your rifle falls between the 1952 serial numbers in red. Those rifles were made in 1952 according to their LBC which is a "D".
Your rifle's Lever Boss Code is THE single most accurate method of determing when your rifle was manufactured. Serial numbers are NOT as accurate as the Lever Boss Code in determing the year of manufacture.
Look, again, at your LBC... it always has an inspector's NUMBER in front of the letter indicating the year of manufacture. Use a magnifying glass if necessary. A "C" alone is NOT the LBC... it is probably just an inspection mark of some kind.
You will find the real Lever Boss Code INSIDE a tiny OVAL lightly embossed on the extension of the receiver (called the "Lever Boss") on the lower, front end of the receiver into which the lever fit and rotates.
Strength & Honor...
Ron T.