big al, To answer your question simply and directly; Based off the pictures and information you have shared, you have a common 1966 half. It is common to find 1966 halves that appear solid silver on the edge. They just like a 90%ers. I have many of them. I can't tell you why they don't appear clad but they are. And even if the metals were mixed on these, they are common enough that they wouldn't hold a premium above typical melt or numismatic value.
OO