This is a hard surface model which is made up from a handful of separated objects bound together with parenting, constraints and a small rig.

The mesh isn't perfect topology as it contains ngons and is quite dense in places. And so therefore, before purchasing this model, I recommend watching the walk-through YouTube video for this product to ensure it is suitable for your needs.

The rivets and nuts have a different material assigned to them, this is so they can easily be separated from the base meshes using the "material select/deselect" tool followed by the "separate by selection" tool. You can then decimate the rivets and nut's to reduce poly count and then join back onto the base meshes.

The materials are procedural, but you should be able to bake them into image textures with some UV mapping and refinement. I would suggest separating the rivets and nuts before UV unwrapping so that they can have their own UV space which will help keep the base mesh UV maps cleaner.