where's the rpm sensor & the reverse switch?

Hi,

where should be located the RPM sensor on my car?
w124
om606 engine,
dogleg gearbox.

I know where the sensor is on my other Merc: auto 2.5d 190

Looking at the same position I don't see it, nor any holes for it (if it's missing).

Trying to get the rpm dial to work....

Also where should be the reverse switch located?

thanks.