[Logician]

From legal point of view I can confirm Wayne's explanations are 100% true.

It does not matter whether you pretend it is your code or not. It does not matter whether you mentioned it belongs to someone else. It does not matter whether it was a paid or free script. It is a violation of copyright unless:
a) You get permission of the author.
b) Author explicitly allowed the action beforehand (eg. in his code he mentioned it can be imported, ported, distributed etc.)
c) It is not copyrighted in the first place as author explicitly rendered it this way.
d) Its copyright expired according to relevant law. (applies after long years)