66 XKE Door lock

I have stripped down one of the door locks on my 66 xke prior to reassembling the door. As usual lots of dirt and grime. When I bought the car (25 years ago) from a good friend there was only one key, the ignition key. Even well cleaned the ignition key will not lock or unlock the door lock. There is a number on the door lock barrel. Is that the door key number?. The ignition key will enter the lock and is an FS series key.
Any advise would be helpful.

Yes, it should be a three digit number.

Many thanks. Yes the xxx number on the lock barrel coupled with the FS series allowed me to order a key from https://triple-c.com/. Very helpful.