.577/.450 Martini Henry headstamp query

I recently received this Kynoch cartridge case from a farmer who farms north of my hometown, Beaufort West in South Africa. He picked it up in the veld. What other dates are known? I have seen
C 1901 I

before, but would like to know if there were any other dates.

As far as I’m aware those are the only two dates with the Kynoch Lion headstamp.