My limited knowledge (could be wrong) is that the '85 California-only cars had the trap oxidizer. 49 state cars not. Recall was pretty thorough, as with all of MB notices, but cars have slipped by with mailing issues, lazy owners, etc.

Easy to tell if the car has a trap ox. Big hell-for-stout cylindrical can with tapered ends under the aircleaner/turbo assembly, left side after exhaust manifold and ahead of turbo. Your description sounds like you have the disease. Very nasty thing -- kills turbos.

The MB recall is in effect but you might have to find a cooperative dealership for record-checking and the actual replacement work. Problem with the replacement is the internal expense to MB and the dealership mechanics trained on W123's are getting scarce. MB will still bear the cost, some dealers are less than enthusiastic. Nevertheless, get it amputated.