early and late W124 trunk lock differences...
 

I am transferring a full set of locks from an '87 300E to use on my '90 300CE. The PO used an ignition lock from another car (after hacking up the guard ring and column mount) and then the trunk didn't open so my body shop drilled it out. more background: http://www.peachparts.com/shopforum/showthread.php?t=199322

The differences on the '87 door lock doesn't have the chrome pieces. I also noticed the electric plug pigtail has a longer wire on the coupe since it's routed and mounted differently.

The '87 trunk lock doesn't have an electric switch that's on the '90. I'm not sure why it needs feedback as my '87 trunk lock operated the door locks without it. I think the early W124's sensed the switch at the master vacuum switch. At least I will have a working lock until I want to spend $400+ on the correct ignition and trunk locks. Removal: the body of the lock just slides apart into two main parts. Pry and remove the round plastic lock housing and o-ring. Remove the part that prevents the lock from being pushed in by twisting and pulling it out. The '90 has more parts to the switch and rod to remember how to re-assemble. I was just going to swap lock cylinders but I broke the plastic arm to the actuator linkage rod. I think in retrospect I will try to slide the lock apart before removing it from the car. By prying it out of the smaller square hole I broke the plastic linkage. The early lock has a stronger attachment to the linkage.

If you have the keys for both, you should be able to push the little pin out of the door lock assembly to disassemble and swap cylinders.

I didn't consider that, thanks!