Congrats, Doc .... Cool acquisition! Much rarer than the tripod and overdate Buffs, methinks.
Having actively collected Buffalo errors myself some years ago, this is the first 1917
DDR I've seen. Contrary to what others say, when it boils down to acquiring truly scarce/rare coins as this piece is, I always discount the condition. After all, a second opportunity to acquire such a piece at a reasonable cost may not present itself in one's lifetime. Few collectors will ever own one of these, much less even know that they exist!
Also, I'm a BIG fan of SEGS quality holders and no-nonsense grading.