Hey guys, I guess the Title says it all.
My master key works in the driver/passenger doors, ignition, and glove box but not the trunk. The key slides in nicely but it won't turn.

Any ideas?

It looks like the PO has done some tinkering here since the actuator to the lock is unhooked. Could this be related?

I have sprayed the lock with lubricant.
87 300D
Thanks!