Prydon's models are all mostly scavenged and derivative of copyrighted work (for example, QUAKE GUY'S FACE ON EVERYONE and the white knight skin, and so on) so obtaining permissions will be hard for you. This is why the readme was like "don't bother stealing ok" in the end.
Chillo however I think did most of the weapon models and Preach did some of the new monsters.
If this is for a GPL project, you might as well forget about it. The sources to the models are probably all lost and probably require a non-Free program to use (qME and its .mdo files)
I wanted to redo all the models to be optimal, memory consumptive and a new palette at one point. Maybe I can still do that now?