Lots of good and considered comments here.

I think the door edge guards are a very bad idea, they look after market and the plastic ones especially, won't stay on for a long time, and they attract rust and dirt. Carefully applied touch up paint as needed is a much better idea

My experience with the chromed wheel arches was this: I added them to a 1991 Volvo to avoid body work after a light scrape on a fender lip. Years later, the car was hit and run, (sideswiped) and 2 wheel arches were damaged with the chrome arches. It was almost impossible to find replacements, and of course, I had to buy four new ones for a match. The paint underneath them didn't match the rest of the car any more, and there was a LOT of dirt, no rust yet. (A fellow in Chicago told me a low mileage, under 40k 560SEL in Chicago had these chrome wheel arches on it, and there was terrible rust underneath them after several years....)

I would avoid the chromed wheel arches, but my question is this:

I have seen many W123 cars with them, were they a factory option or feature, for some W123 models? I actually think these cars look nice with OR without them.

Chrome wheels look fine to me on most any W123, but they are more high maintenance than the alloys. I have heard the 15" chromed bundt cake wheels are very rare, and expensive. Ronal, BBS, and AMG Penta wheels look good on them too.

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1991 560 SEC AMG, 199k <---- 300 hp 10:1 ECE euro HV ...

1995 E 420, 170k "The Red Plum" (sold)

2015 BMW 535i xdrive awd Stage 1 DINAN, 6k, <----364 hp

1967 Mercury Cougar, 49k

2013 Jaguar XF, 20k <----340 hp Supercharged, All Wheel Drive (sold)