Different style guides give different answers so you'll find someone to support most any way you decide to go.
There is currently a bill in the Arkansas state legislature to give a final determination on whether the possessive of Arkansas is Arkansas' or Arkansas's.
AP style guide requires
always adding 's to a singular noun to make it possessive. The New York Times styleguide would have you using Productions' without another s. The Chicago Manual of Style uses 's unless the final S in the singular noun is silent (Camus, Francois, Arkansas).
Way too much detail
here.
So the key is to pick a style and just be consistent with it.