Proper credit is VERY important. My pertinent example is the turd formerly known as JSTARK. He is famous for "inventing" the FGC-9. He did not. He very poorly ported an old, out of date design to metric and did such a poor job of it that it became rather notorious for OOBs (out of battery ignitions of ammunition). He did not attribute the original design and outright refused to do so continually. He's a turd for that, even if he didn't deserve to get offed.

I HATE that kind of thing. But, the design was open source so he did what he did and now he's infamous.