To be honest, I think you need to know at least a minimal amount of rules as a GM/DM. While I love 3E/3.5, I honestly have not had a lot of time to play the game since it came out - first, I got a new job that required me to work sweatshop-like hours, and then I got married... and, as soon as I had gotten around to finding a job with more reasonable hours, my wife had to go give birth to our first child. Then, when that settles down and gets to be somewhat regular, the DM of my old group goes down & has to have major surgery, and we also moved from a 35 minute drive from him house to about a 60 minute drive.
So, I seemed destined to not be able to play 3E.
I was later approached by some guys looking for a DM (their old DM married & then moved) and I was intrigued, even though I hadn't DM'd regularly since 2E days. While that ended up falling through, I would have gone into the game as not having actually played 3E/3.5 much at all and with zero XP as a 3E/3.5 DM. I told them up front that I would strongly suggest that we stick to the main 3 books - PHB, MM & DMG., which was fine with them, as that is what they normally did, anyways. But, I would have had to have relied on their rules expertise when it came to running combats, spell effects, etc, at least until I got more up to speed.