Today I found (among other things) a very shiny, smooth but worn 1964-D Jefferson. It looks a bit off, maybe the typeset used is a tad different. But anyhew, it has the D mint mark located in a neighborly position to the due east of Monticello. Any takers? Also, see my post in 'Found in Circ' thread.
Mint marks on Jeffersons were on the reverse through 1964, moving to the obverse in 1965. At about 1.8 billion minted, I believe your 1964-D is the most common date produced.
As I went through dozens of rolls of Jeffersons to complete my collection, the 1964-D turned up more often than any other.
Mintmarks were moved to the obverse in 68 not 65. (From 65 through 67 they didn't use any mintmarks.)
