When they went to the MK2 range the YDO body codes were stamped in the gutter above the wiper motor. The Code for the Cooper S was 2/06 and the Mini K was 2/05. The MK2 matic used the same 2/05 body code with an A stamped after it. The body code stamping moved to the firewall behind the master cylinders around May 1970.
Here is a 1969 Cooper S stamping
Attachment:
2-06 659 Gutter.jpg
Here is a 1970 Cooper S stamping
Attachment:
2-06 1588 Firewall.jpg
Here is a 1969 Mini K stamping
Attachment:
2-05 1266 Gutter.jpg
Here is a MK2 Matic stamping
Attachment:
2-05A 1969 Mk 2 Matic.jpg