The 108/109/111/113 shop manual shows that the floor shifters changed in May 1969. This change coincided with the the introduction of the automatic transmission K4C-025 and the lateral shifting manual transmissions. The transmission tunnel had to be enlarged to allow the use of these transmissions. I don't know 114/115 cars very well, but I think they used the newer transmissions from the start of production in 68. The mercedes EPC would be the best place to verify what transmissions the 114/115 cars used.

The 113 continued to use the older K4A-025 automatic and top shifting manual transmissions till the end of production in 1971 and the shifter never changed.

John