CAN-bus in A2 2004?


I'm new to A2OC.
I picked up my MY 2004 A2 today.
Prior to getting the car I already looked around for things to add and found a reasonably priced Concert II. After reading posts on this forum I expected to find a CAN connection in the dashboard to connect the Concert II to. But it doesn't seem to be there. After pulling out the non-standard head unit the car was equipped with I only found the loudspeaker and 12V/ground/etc. connectors.
Was the CAN bus optional and is it possible that a 2004 A2 doesn't have it?
thanks for your reply.
I have tried to "fish" but other than scratched hands I didn't get anything.
Is there an easy way to remove the airco unit and/or the compartment underneath it? That would give me more visibility and room for my search.

(sorry if this is an obvious question. I have searched the forum but apart from a "how to" on modifying a Sat Nav unit I couldn't find anything related)

yes. Pull the aircon unit towards you, there are four connectors on the back. The drawer underneath will come out when you open the ashtray and then pull that, too.