There are shifter bushings inside the vehicle on the shifter assembly, and a set of 2 bushings on the shifting linkage in the transmission tunnel. The latter two are the ones that generally cause the most problems when they fail and disappear. If the bushings in the shifter assembly have failed (far less common than the ones under the car), they're worth replacing to improve the feeling of the shifter, but they shouldn't cause the issues with engagement and no-start like the main shifter bushings under the car do.

__________________
Current stable:
1995 E320 157K (Nancy)
1983 500SL 125K (SLoL)

Gone but not forgotten:
1986 300SDL (RIP)
1991 350SD
1991 560SEL
1990 560SEL
1986 500SEL Euro (Rusted to nothing at 47K!)

Gone and wanting to forget:
1985 524TD 167K (TotalDumpster™) [Definitely NOT a Benz]