No I didn't get the nav, the back up monitor was a stand alone option that listed for 350.00 I think. When we agreed on the price my options were Premium Pkg, Heated seats and the backup monitor.
FWIW: When I bought my (new) 09RX350, I was told the camera came with the nav. package, but was unavailable otherwise. I have since had (rear) parking sensors installed. They work fine, indicate the distance (in inches) to contact quite accurately, and cost $190 incl. install.
The parking sensors that you had instaled...were they Lexus or after market. Lexus dealer do the install? As I ordered my 2010, this is something I couldnt believe Lexus has not included, even more that they have the back up camera. Even my Ford F-150 has both the sensors and camera.