Robert - I had to do this when replacing the a/c condenser on my 1990 560SEL. It's quite a bit trickier than on the earlier one fan W126 bodies (early diesels) and you have to remove the shroud and fans, whereas on the single fan models you can access the condenser without removing either shroud or fan.
You can remove the shroud after pulling the plastic rivets, which you have already done, but the problem is the shroud interferes with the crosspiece above the radiator. Check my slide and make a few peace offerings.... I'm pretty sure your late diesel is identical in design to the two fan 560SEL.