I'd say you have a 1960 Sea King; hard to confirm the variant for this. I found one 1960 ad that appears to match this watch, at a cost of $49.50, but with no variant mentioned:
Using the possible price of $49.50 and referencing the pricelist from 1961; there were five Sea Kings at this price (two of which were black dials); possible matches could then be either the 'D' 'E' or 'GW':
Link to 1961 'D' ad
Link to 1961 'E' ad
Your watch does not match the D or E, so it may be the 'GW'; but without a positive ID to an ad or a tag on your watch showing the 13260 or 'GW' or other, we can't match it to any of the possible variants. We'll see if any other members find something more concrete...
It's also very cool to see what would have been displayed in the store back in 1960; certainly gets your attention.