I still check Denver coins. You might just find the first example. That is how I found the first 2002-D
DDR on EPU:

I knew the 2004's had the EPU doubled, So I checked all years of the Zincolns for the doubling in that area. It paid off. I think there are about 4-5 examples known by me of this die so far. A lot more out there that are missed.