The final figure in the single boxed like is the Action Sailor Keychain. Released in 1997 as part of the 40th anniversary line. Hasbro didn't release any 4 inch scale figures as part of the anniversary, so had licensed the figures to the company Fun4All who released a series of 4 keychains in single boxes.
The box on the Sailor is exactly the same as the rest of them. The wooden style shoebox with open window where you can see the figure inside and the keychain attached to it. There's a classic GI Joe logo on the top and an anniversary stamp underneath the window.
The back of the box features the same GI JOE logo, this time in green. Large artwork of the 1964 figure and a graphic of the figures in poses. Underneath that there's simply copyright information. Like the rest of the figures, the box back is very scant
Taking the figure out the box, we can see that it is exactly the same as the black retail version of the Action Sailor. He has no accessories from the figure set, just the keychain that plugs into his back. Like the others he's identical to the 1994 releases, except that he's made of a much cheaper plastic, which means he'll break very easily.
While not a picture of the Sailor, the Marine demonstrates the different versions. Like the others, the first release Sailor had a plug that covered his back whereas the later release ended up between his shoulders.Neither version is more rare or collectible than the other. It's not uncommon to find these plugs snapped off in many secondary market finds.
Fans of this series can get a complete set for £20 in box with shipping from the USA, or cheaper if you went loose. While not a bad figure overall, the fact it has no accessories and is fragile might turn off a lot of collectors from wanting to own these overall. But as I always say, Your mileage may vary