3rd party files in unity asset?

I have an world generator asset using whydoidoit's free multithreading script, and i want to use the Unity Robot Mechanim as a player in the world environment of the asset to show the asset works with Mechanim. If there is a free helper script without any copyright text, is it ok to just include it with credits? what can i put in an asset and how should any helper scripts like keyboardorbit etc be credited? in the actual code? in the readme file? Thanks!