sorry it took so long to get back to you. go to 3d stamps then underneath it where it says models, find your model.
It will show a panel on the right with material 1 - in that box is a little white icon with an arrow pointing left.
this will show THAT model's material settings. in the middle of the panel on the right is where shader settings are, a)n, map_nolit, whatever, etc. that's where you can change its shader style, as well as the UV map that it uses.