No... absolutely wrong... Do not pry door panel.

_____
_NOT_CORRECT_!  The 300SD is a W126 body style car, and the door panels
_SLIDE_ down into place.  The more common snap-in buttons are not used
on this model.  If you use a fork like tool or a screwdriver you will
break the tabs that hold the panel in place.  The tabs are molded onto
the plastic material and are very difficult to reattach.  Ask me how i know!

Door handle problems are common in older 300SD cars, especially the
driver's door because it is used so much more than any of the other
doors.  The first thing to remove is the thin, concave black plastic
cover under the door handle.  This is done with small 1/8 inch
screwdriver by prying at the front of the cover.  Remove the cover to
expose the screw that holds the entire black metal/plastic handle frame
that sits on the wood veneer.  Remove the two large self-tapping metal
screws that hold the armrest in place, and the third small screw hidden
under the handle cover you just removed.  Slide the handle frame down a
little along the top end of the armrest.  This exposes a third screw
that holds the armrest to the door frame.  Remove the large screw (it
has LockTight on the threads and may take a lot of force to unscrew).
Now you can remove the armrest and the door handle frame together.
Remove the door lock plunger (has regular right hand thread).  Remove
chrome door latch trim.  Remove two small metal screws from front of
sloping window channel, and pull off plastic trim on inside of window.
Now push _UP_ on the door panel from below and slide it off the metal
door frame.  This should be fairly easy.  When the panel is loose, pop
out the courtesy light at the bottom, and pry off the electrical
connectors on the window and seat switches.  The courtesy light can be
pulled through the hole in the panel by turning it 90 degrees.  Remove
the plastic vapour barrier sheet on the metal door frame taking care not
to tear it.

The inner door handle mechanism is made of pot metal (brittle) and is
likely broken.  It activates a rod that goes to the latch mechanism.
This mechanism may also be broken, or the rod has come out of a pivot
point.  Repair or replace broken parts.  Replace vapour barrier.
Reattaching the panel can be a bit tricky.  All the tabs _MUST_ slide
into their slots at the same time.  I usually squirt some silicone lube
on the tabs and the slots in the metal door frame to make it easier.

I am writing this from memory, so i hope that i did not miss a step.

Regards / jch

Doesn't matter, it's the same procedure.