Now that't the way to mark the shafts.

A fun fact: On the four cylinder 230's that were built up to 1976 the engines were so short the transmission needed to be moved forward a few inches. Mercedes decided that a two piece driveshaft would be too long and would induce vibration.

So they used a three piece driveshaft. With two carrier bearings.

There are not many of these left running, but if you have one be ready for a fun filled day of wrangling a three piece drive shaft which no one in the US is set up to balance.