Charles (of Virginia) sent me the complete package needed. To make amends for giving the wrong information in this thread. What a gentleman.
As was stated above by Stan, here are the 3 elements needed to fit a viewfinder eyecup on a D7000.
a) DK 22 Eyepiece adaptor (for round eyecups)
b) D-3 Eyecup (not the D-19)
c) FE-FM Screw In diopter lens --- to hold a & b together. Available in varying magnifications, so get the 0 add, since the D7000 has a built-in variable diopter on the viewfinder. This threaded part was made to fit the FA-FM2-FE2 cameras.