I had investigated having a 96 C lock cylinder cut to replace the 97 C IR. The dealer said they would likely have to send special instructions to New Jersey that we really wanted a 96 lock coded as the 97 car. ( 96 still had a key lock on the drivers side )

In your case, there might be a difference as 98 has the electronic key fob?

Another possible work around is using the 97 C / E passenger lock on the drivers side. The complete unit is the same left to right except for a band of chrome trim, I'd expect the cylinder to be same and swappable.

When I removed the 97 IR "lock" from the drivers door, there is plastic blocking the door locking mech , this plastic is part of the IR wiring socket. I'm trying to get a hold of a parts car for more invasive investigation.

Also, my 97 SL has a key in the drivers door but none on the pass, this is invaluable as the IR is disconnected due to random alarm actuations.