No, it has a timing chain.
http://www.clublexus.com/forums/showthread.php?t=338155
The Lexus GS300 qualifies as a midsize sedan. This is a great car, and it has only improved with each new generation Lexus has released. Its latest design was in 2006; however, the 2006 model was discontinued after a year and then rereleased as the GS350. Lexus made the GS350 in a response to the consumer complaints about the lack of power in the GS300. The GS350 was released with a 3.5 Liter V6 engine. Both the GS300 and the GS350 are identical except for the beefed up engine. Hope this helps.
PLIZ HELP How can i reset the injector maintenance required in lexus gs350 2012
The 2007 Lexus IS-350 is 15 ft. 0.1 in. (180.1 in.) long.
The 2007 Lexus IS-250 is 15 ft. 0.1 in. (180.1 in.) long.
The 2007 Lexus GS-450H is 15 ft. 10 in. (190 in.) long.
The 2007 Lexus LS-460 is 16 ft. 6 in. (198 in.) long.
The 2007 Lexus RX-350 is 15 ft. 6.2 in. (186.2 in.) long.
The 2007 Lexus ES-350 is 15 ft. 11.1 in. (191.1 in.) long.
To replace the bulb on a 2007 Lexus GS350, first, open the hood and locate the back of the headlight assembly. Depending on the bulb type, you may need to remove the dust cover by twisting it off. Disconnect the power connector from the bulb, then twist the old bulb counterclockwise to remove it. Insert the new bulb, ensuring not to touch the glass with your fingers, reconnect the power connector, and replace the dust cover.
Lithium CR1632 (2008). I just replaced mine and got it from the dealer.