lock barrel interchangeability

Now that I've fitted door lock motors the passenger door lock is redundant. My fuel cap lock is different to the rest, so I'd like to replace the fuel cap barrel with the one from the passenger door so that the locks are suited. Is this feasible?

I can't answer your question directly but when the fuel filler lock on my mums metro played up I dismantled it and removed all the tabs to make it possible to unlock it with any key of the correct profile. With that in mind it may be possible to modify the barrel with the tabs from the door lock.