1964 Date King H with original band
The 'H' variant is a 14kt gold case, which the subject watch is not. This one is similar to the watch discussed here. We also have similar calendar models called Presidents around this year, with 30 jewel movements in some.
Date King (no variant found)
In reply to The 'H' variant is a 14kt by Andersok
I see a older discussion around a 1964 Date King E - where there is belief that the 14kt vs. 10kt doesn’t matter very much, because the pointed markers at the 12,6,9 looks more like a "Date King" dial than a "President" dial. It is pointed out in the discussion that the 'PRESIDENT' replaced 'DATE KING' in '64 as the ad states 'new', which would make more sense. The final assessment is that it remained a 1964 Date King variant E, but this case is Stainless Steel with no gold at all. It should be interesting to see what your final assessment is.
I did find a Date King "BB" don't know very much about it http://www.watchophilia.com/vintage-advertisements/a1960-1969/a1965-newspaper2/
I was looking for more information on Date King H and 14kt vs. 10kt and I came across this watch on ebay
The watch is shown with the box and documentation authenticating the watch to the watch serial number. Now the reason I am brining this up is the watch is a 10kt case not the 14kt case which supposedly the Date King H should have?
In reply to I was looking for more by MGD001
Sorry MGD - I edited the eBay link from your comment as we do not allow links to active eBay listings. Once the listing closes or sells it is allowed. No harm, no foul.
The listing you linked was not a Date King H, it was a Date King watch with a SERIAL number starting with the letter H.
In reply to Sorry MGD - I edited the eBay by Geoff Baker