Ceramic sub date on a m series

[scooba]

Hi collected my ceramic sub yesterday and was suprised by the serial number.


Its a M and its not random, its one of the old serial numbers M9856--


SO why is it such a old case number ,could it be as suggested possibly a prototype or very early production watch in storage.


I have had 3 V series in the last 18 months .last time i bought a Mserial number was Nov 2008.

any one have any thoughts TIA