Whoa, I don't recall ever seeing '66 sedans with those. Both of mine didn't. The Java Green car was so late, it had '67 outside door handles with the passenger side plain (no keyhole).
I hope that you're able to get a set of those, Pupjoint.
Fred, there were two types of door handle in '66 and another in '67. The early '66 had the same handle as the '65 and earlier, with the square push button, and the later one had the round push button, like the '67 ones. The difference is with the way they mount in the door - '67 handles have one screw, '66 and earlier have two, so the round push button '66 handles have two screw holes, making them really rare as they were only used for around four months. My Bahama blue '66 had those round push button ones, and I don't remember seeing those plates. My race car was also a '66, and had been fitted with pre-'60 handles, and that definately didn't have them. I don't know if that was an early or late '66 originaly though.