Did those actually reprint any existing Open Game Content, or did they simply introduce Open Game Content of their own?
From Unearthed Arcana:
15. COPYRIGHT NOTICE
Open Game License v 1.0 Copyright 2000, Wizards of the Coast, Inc.
System Reference Document Copyright 2000-2003, Wizards of the Coast, Inc.; Authors Jonathan Tweet, Monte Cook, Skip Williams, Rich Baker, Andy Collins, David Noonan, Rich Redman, Bruce R. Cordell, based on original material by E. Gary Gygax and Dave Arneson.
Modern System Reference Document Copyright 2002, Wizards of the Coast, Inc.; Authors Bill Slavicsek, Jeff Grubb, Rich Redman, Charles Ryan, based on material by Jonathan Tweet, Monte Cook, Skip Williams, Richard Baker, Peter Adkison, Bruce R. Cordell, John Tynes, Andy Collins, and JD Wiker.
Swords of Our Fathers Copyright 2003, The Game Mechanics.
Mutants & Masterminds Copyright 2002, Green Ronin Publishing.
Unearthed Arcana Copyright 2004, Wizards of the Coast, Inc.; Andy Collins, Jesse Decker, David Noonan, Rich Redman.