Got this same problem as well, and am going to look at it today.
I called the MB dealership and inquired about these bushings for my '91 300E, and he said he saw 2 bushings that I mentioned but both were identical with the same part numbers.
Partshop shows 2 different bushings, one on the shift rod, and one on the "tapered spool", both different part #'s.
My question is: is this tapered spool one of the areas that a worn bushing will cause the "slop"? Or do I just need 2 identical shift rod bushings to complete the job?