Got a pm today and thought I would share the question and response for the benefit of all.
"Hello there, I am working on a 1998 E300 turbo diesel AC system and have been searching and searching for info on the “updated dryer to condenser hose”. I see that much, but cannot find out how to tell if I need it or not, how does one tell if the line is the original or the updated line that will fit new accumulator/dryers?"
The hose p/n is 210-830-46-15
https://www.pelicanparts.com/More_Info/2108304615.htm?pn=210-830-46-15-MBZ&SVSVSI=3742&DID=9852
I would recommend replacing the hose if it looks original. It is exposed to the road and gets exposed to damage from road debris. My hose had damage so it was good that I went ahead and replaced it.
BTW the a/c was still ice cold when I sold the car to TimFreeh this summer...and I never touched it again after John charged it the first time.