Texture issues using pre-made 3D models !

So, for context- I'm making an effort to convert some 3D models from "Portal" into sims Custom Content. For the most part, it's working out all right- I use blender and sims 4 studio to turn it into a package file, the works, but the textures on all of them always seem a little off, in one way or another. I'll attach some images so it's a bit more clear, alongside what the models are actually supposed to look like. I'd really appreciate some help here! >:/
imgur.com/a/kXT1Lga
(the button model's a little saturated, but oh well.)