Does timing belt on 2004 Lexus RX with 200,000+ miles need to be replaced a second time? Had it done at 100,000 miles.

Yes absolutely. Lexus specs say 90,000 miles or 120 months, 10 years whatever comes FIRST. And the 3.3 is an interference engine. http://www.clublexus.com/forums/rx-second-generation/725725-2004-rx330-timing-belt-replacement.html

Running well and no leaks is all well and good, but has nothing to do with timing belt. Actually is is not likely to break, some of the people on the Lexus forums run theirs 120,000+ miles but that is the far upper limit. But if it did break you are talking major engine damage. Have the water pump done while they are in there if you opt to have it changed I realize I am talking as if it has never been done, but when you had it changed at 100k the clock starts again, after another 90k according to the Lexus maintenance schedule.