That's a nice find. I have found two doubled dies in the past year. One is the 1984 DDO-001 and the other is a 1964-D
DDR (not sure which one). I do a lot of roll searching from banks. I think this is a fun and very inexpensive way to find some nice coins. Especially where I live. I live in a very small town in Kentucky and I don't believe there are very many other error/variety hunters here.