If the demand is there and it will help drive sales, then do another run of Kirk and Spock. Though I do think it would be missing an opportunity to not do any proposed second TOS Kirk in the green wraparound instead, as you know lots of fans would happily double dip for that (and having two Kirks, a few more might buy the Captain's chair then, too). Hell, just make both of them Trouble with Tribbles based releases, that way you'd get Kirk in green, and regular Spock, pack in some tribbles with their regular accessories, and call it a day. A tribble top up bag might be a fun, and cheap, con/website exclusive, too, and would give early adopters a way of getting tribbles for themselves if they wanted them, without having to buy kirk and spock if they didn't wish to.
Just an idle thought, anyhow.