GREAT SCORE!
I would crack it out and send it to ANACS for UDU attribution. They will attribute it and the pop is only (5) right now. These are MUCH harder to find than people imagine. I am convinced that the die setters didn't know about the UDU when they pulled a clashed die for abrading AT THE BEGINNING....but they soon caught on, and began abrading that area as well.
This is a conclusion I drew from examining a LOT of clashed 71-S Ikes. Many of the clashed dies are abraded in the WE UDU area, and VERY, VERY few are abraded in ALL of the other clash "Spots" except in the UDU area. Since it was the first time they were stamping these puppies out,....it took them awhile to recognize the clashing areas that needed to be abraded. I doubt that one would find any UDU Silver Ikes after 1971.
The "Clashed E Reverse" is one of the most sought-after Morgan VAMS...because of a clashed
LETTER on the reverse. The 71-S UDU Silver Ike is even better! Here, we have a clashed letter on the
obverse!

I predict the 71-S UDU will go down as one of the BEST Ike DIVA's ever!
Does your UDU have a nice TH as well?...or was it abraded?
GREAT score on the TDO as well! Can't wait for the pics.
edited to add: Maybe you don't want to crack it out...just send it in and see if they upgrade it.(I know they would at least keep it a 66). None of the (5) attributed UDU 71-S Ikes at ANACS are a 66! That would make your coin a top-pop if they crossed it and kept the same grade.
Happy Hunting!
Brian