Yes, all 140 and 129 owners should be on the lookout for leaking steering gear boxes.
Recommend a reman (if available from MB) or a new box if no reman is available. Problem with resealing the boxes is that several special tools are required to do the job correctly, but they aren't tools that MB requires the dealers to buy, so few have them.
Seen cases where shop #1 tried to reseal, then owner brought car to shop #2 for a proper repair, which is to either buy the tools and do a proper repair, or sell the owner a different box. Owner was of course "out" on job #1.