I dismissed this 1973-D Kennedy as MD... Sure looks a heck of a lot like 1974-D DDR-001

Just put it in a flip and took a 2nd look on VarietyVista to notice it sure looks a lot like the 1974-D DDR001 - http://www.varietyvista.com/12 Kennedy Halves/DDR Detail Pages/1974DDDR001.htm
There isn't one listed for this 1973 D
From Variety Vista...
the 1974-D DDR001
Coins are Neato!
"If it's a penny for your thoughts and you put in your two cents worth, then someone...somewhere...is making a penny." - Steven Wright
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Comments
Looks like classic machine doubling to me.
Your coin is only showing machine doubling. The coin screen shot from Variety Vista is both machine doubling and a DDR.
The Stage B pictured in the Variety Vista ebook is much more indicative of the variety, as the machine doubling is gone (the reverse die is tightened.) It's classified as a Class II + VI, and it's a very minor doubled die.
I'm going to throw a couple of words out, that I. and a few others, have been using pretty much lately. "Wishful Thinking". Lol. I've been doing a lot of that recently.
"Jesus died for you and for me, Thank you,Jesus"!!!
--- If it should happen I die and leave this world and you want to remember me. Please only remember my opening Sig Line.Looks like machine doubling... at least in all the pictures in the OP.... Cheers, RickO
I always temper the wishful thinking
It only takes about 4 decades lol.

In this case it was taking a final look at it a couple hours past my bed time
Coins are Neato!

"If it's a penny for your thoughts and you put in your two cents worth, then someone...somewhere...is making a penny." - Steven Wright
MD
Kennedys are my quest...