What if a weapon is already textured?

[What if a weapon is already textured?]

Right here:

http://www.sharecg.com/v/18574/related/5/3D-Model/AR-10-Machine-gun

http://www.sharecg.com/v/18577/related/5/3D-Model/AR-10B-Machine-gun

http://www.sharecg.com/v/18269/related/5/3D-Model/AR-10T-AMT

all three made by the same guy, But they are all pre-textured which is my problem.

[What if a weapon is already textured?]

Hello, I've recently started modding but I was wondering something, I had downloaded a free 3d model of the AR-10 but it is pre-textured and if I import it into o2, it will not load the texture because I don't have a copy of the texture. Just only on the model. How should I go about removing the texture or loading it (if possible)?