I believe just gluing both pieces together, even with epoxy, is not durable solution. I would prefer cutting off of rest of dovetails, clamping bot pieces together in final position and drill trough both a hole for stronger nail. The length of hole must be shorter than the nail. If you make before on top and little bit wider hole you can cover the head of nail by tin dovetail and paint as many of us already proposed. After such wide discussion it would be interesting to know what solution you have chosen...

best regards