All are 100% legit, but I have strong doubts about the one in which he is fighting the T-Rexes.
I obtained that one from EMP back in January, so I hope it's legit.
I thought that one was the single-sided, special mail in poster.
Perhaps our resident King Kong guru (aka, Ted) might know more.
I would definitely like to know more about what gives you doubts. Thanks.