That is fine, but what if the rectifier is still fine, but the voltage output is still too low.
AFAIK, the voltage regulators on these cars arent even 14.1V. This is a problem for many modern battery chemistries, which like a good charge up to 14.1-14.5V.
A battery is full when it takes less than 0.5A at somewhere in that 14.1-14.5VDC output range. It is a lot more difficult to fully recharge a battery at 13.4V, which is roughlhy what the DC bus in a w123 seems to be.
If on a working alternator, the output stage can be fooled into slightly higher voltage, there is working benefit across the board. Im not proficient enough to say if this is a good/bad/right/wrong way to do it, I just too would like to see slightly higher operating voltage.