2 letters on date stamp?

seahorseinstripes

bag greed bug
O.G.
Jun 4, 2006
16,089
189
hi! from the threads i learn of the date stamp but still confused.
my herbag is a letter C and D in square, the D in square meant year 2000
but what does the C means?
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thanks and sorry if it's been asked several times :shame:

xoxo
newbie