Customization

Hi everyone!
I am a game design and graphics student, and I am writing my thesis on customizable objects in games. I am focusing on objects and not characters. During the project I will create a gun with customizable features. The players can change perhaps the grip, barrel, and magazine.

I was wondering if any of you have any tips and tricks when working with customizable objects? Does anyone have any good links to videos where you learn about the technical aspects of customization, what one should do with the textures, or adding bones etc?

Thanks!