Model 584
was a promo model, introduced October 1964 and made in somewhat limited quantities until December 1968. The 584 was a blending of deluxe and special Convertibles, it had a full bumper and the zipper bag of deluxe machines, and the short cord/no headlight of the special models.
Its colors are garland green and pearl white, although the final models are painted light seal griege.
I'm at work, so I can give you the number produced.
I have a really early 584 in my collection from 1964. It has the large medallion, the shoe string thingy in the bag spring, and the speed switch under the casting.