I have a mid 90 build date on my 300sel, so I'd venture to guess the white fan is the updated/late one.
Either way, I have no overheating nor do I have cooling issues. Most of these cars I have purchased all had original radiators, hoses, belts at times!, thermostats, etc. I dropped about 3-6°C when installing JUST a new radiator in my 300SDL.
Significant drop.
I opted to go with the higher thermo for the M103. There's an 87°C or the 79°C, 188.6°F or 174.2°F. The latter just seemed too low for winter use for proper operating temps. With the 87°C I never get past 95°C at idle in traffic in the summer.
If you can't drop $600 into a cooling system rebuild, you should probably rethink these cars. Then people balk at spending a few hundred more to replace all the vac/rubber connections under the hood too... makes me wonder at times.
They're cheap for a reason, NEGLECT.