Does anyone know the process or type of finish that Mercedes uses to finish the wood trim on the dash.

I don't know MB's technique, but I know what worked for me when refinishing some Zebrano pieces.
1.) Be patient. Remove old cracked clear finish (epoxy type?) with gel type stripper being accurate and careful so as to not lift veneer or melt any plastic clips or backing. Judicious!! use of a dull putty knife helps.
2.) Use a "grain sealer/filler" (available where fine furniture refinishing products are sold). Sand with very very fine sandpaper.
3.) The wood will be really "bleached" looking at this point. Use a stain. I use red oak stain now; have used mixture of redwood and dark oak stain, some use cedar and oak, some mahogany. Each car has slighty different wood shades that can be a challenge to match. Experiment on a scrap piece of pine to get close.
4.) Use Flecto Varathane Clear Finish Gloss spray. Follow proper spray protocol (room temp., indoors, but ventilated). I really give it a good covering, dries fast, watch bubbles, 5 coats!!
5.) Let it dry completely! and then sand with 800# sandpaper (coarser, if you screwed up(who me?)) Apply two more finish coats.
6.) After all this, for the next piece you do, call every salvage yard that has your vehicle type and buy the best replacement piece you can!!!

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The Golden Rule

1984 300SD (bought new, sold it in 1988, bought it back 13 yrs. later)

i was able to replace almost every single peice of wood in my car for about 200USD$. not bad if you ask me. bye the way car is an 83 300SD
R