"I am about to embark upon a project to replace a fender--something
I've
never done before, as I have always combined my projects to engine and
running gear-related tasks. This is a right front fender. Is this
something
that a non-body man should tackle? "

I just had a fender replaced in a 1980 116 by an experienced body man
who I know pretty well.
He told me it was a real bitch to get off and I could see why.  It's
bolted on, but MB used
a thick rubberized type of coating over everything.  He eventually had
to use a torch to melt
the stuff so it would come apart and even then it was a bitch.  Don't
know what they used on
115, but if it has the same coating, it could be a real pain.

Another issue is what fender you're replacing it with.  According to my
guy, the aftermarket ones
usually don't fit right, some don't even have the mounting holes
drilled in them.  We went with a
MB OEM one, which cost a lot more, but in terms of time and trouble,
was worth it.

Mostly. It just unbolts. Then you have this f'ing nuclear glue
to deal with. Heat helps.

i actually just went through the same sort of work on the first of two
fenders for a W123 the other weekend, and frankly it wasn't nearly as
complicated as i thought it would be.  In my case, i was fortunate
enough not to have any trouble with the PVC holding the panel (phew) but
i didn't have much trouble with the fit of the new panel, nor did the
whole process really take very long.  admittedly, i had help from a
freidn far more experienced in body work than myself, but i'd say it's
certainly worth a try.

They should bolt right off, inspect the inner wings when you take them off
as they are rust prone