Avoid opening the lock cylinders
I played around with a cylinder thinking I would open and clean it.
All bullets and springs pop out and you will never get it back properly. I would strongly recommend you to skip it.
Why do you want keys to match? A coupe is best left open. If somebody wants something in your car, it is better they use the normal opening mechanisms rather than destroy metal, paint, chrome, glass or door locks. Nobody steals an old stereo part these days.
Just my way of reasoning. I never lock my coupes (or park them in public places overnight).