Pete,
There are three versions of the US spec headlight doors, and I believe there are different socket and reflector assemblies for each as well. The first had suffix AC; the middle, AN, and the latest one has -AJ. I know the -AJ is still available from MB, the earlier ones I don't know. I do know that the only reflector/socket assemblies available are for the latest -AJ. When I discovered this I simply (and expensively) just changed all the headlamp assemblies and sold the old ones on eBay. You really have to have everything match to look right.
The socket/reflector assemblies on the latest -AJ version have additional sockets to hold the plugs from the side markers; for a better and more involved description, look up my post from earler this week on side marker positions; it was a reply to a post from Richard that showed the side markers in the wrong position.
The part numbers I have might be old, but:
113-826-04-89 LE 1657 AC 230/250/280SL's to chassis 5607
113-826-05-89 LE 1657 AN Chassis 5608-11947
113-826-06-89 LE 1657 AJ Chassis 11948 to end of production
Note the "LE 1657 AX" number is molded into the front of the lens. Note this is only US spec lighting. I ferreted this information out from a variety of catalogs as well as ordering a bunch of incorrect parts over a period of many months...
Hope this helps. When it comes to proper part numbers and current parts availability, always a good idea to check with Tom Hanson of Caliber Motors.
Michael Salemi
1969 280SL
Signal Red w/Black Leather
Restored