Not really, owned an RX, second generation and currently on the third generation and driven a GS. Both are MUCH quieter and luxurious than the previous gen IS which has now become VERY VERY good indeed.
Things like the tyres need to be put into perspective, as well as the road that it is being driven on. Even a slight opening in the window could have lead to an increase in the wind noise. For example, if your car is running on a tyre which is rated at 65db, an RX riding on tyres with a 72db rating is going to make a huge difference.
Personally, I dont think there is a car on the road which is as smooth as the Lexus hybrids not including the CT.