I think that picture was before there were Century conversions. I think it was probably before the 681 was introduced, so when the 680V and 680W were new, because I believe the 681 brought in eyebrow windows, and I don't see any eyebrow windows in that picture.
That cargo door caught my eye as well.
The Jet Commander in the picture was Rockwell's demonstrator, which was then sold to Riviera Motors around 1968 or so, right at the end of Jet Commander production and just after the sale of the 1121 line to IAI. They needed to get rid of the last inventory (the demonstrator), and I would guess made Riviera a heck of a deal.
Funny trivia: the demo pilot, a guy named Clark Hill, came with the airplane!