My understanding is that surface finish is more a product of the mold than the material and that KAM is just inherently shiny whereas KAT is not
That's it exactly. They both use the same material, the difference is KAM molds used to be shiny by default. Biip with KAM Wraith made them build new matte molds for KAM so i suppose that now there's the option for both.
That said I'd prefer that set in shiny finish, it will complement the colours quite well.
