Note that thefemmedm's answerthefemmedm's answer indicates a spot in the book where you can look this up directly.
D&D3.5 was first published in July, 2003. Anything published by Wizards of the Coast after that date will almost certainly be for 3.5. Anything published before that date will certainly be for 3.0.
Except... Some books published close to the release of 3.5 (Book of Vile Darkness, Savage Species, a couple FR books) were published in a weird "3.25" state, using only some of the rules from the upcoming 3.5 (which had not yet been finalized).
Another source of information is vendors like Amazon.com. The edition will often be in the product description, as it is here: http://www.amazon.com/Complete-Warrior-Dungeons-Dragons-Roleplaying/dp/0786928808
Or, for your specific examples:
Sword and Fist: 3.0 (too old to be 3.5).
Complete Warrior: 3.5 (according to Amazon.com).
Based on my memory, Complete Warrior is essentially the 3.5 equivalent to Sword and Fist.