Recently bought an '88 240 sedan with locked trunk and no key (owner's key which opens everything missing, but valet key for doors and ignition came with car). I discovered that both keys use the same cut pattern but are made using different key blanks. The all-purpose owner's key uses the thinner blank (grooves appear shallower) and will thus fit into the trunk lock. Most key makers will have both blanks. Simply have them copy your present key to the thin blank, and if the lock is original it will work in the trunk lock.