Hm, this is very difficult, because if the interface is stored correctly inside of the middle console behind/underneath the stereo there is anything to see but the cable for the iPod or the standard mp3 player.
I will attach two pictures that might help you.
- First one is while fitting and testing the interface with my standard mp3 player BEFORE storing in the console
- Second one is AFTER storing the interface in the console. As you can see,you can see anything

Today I place the iPod in the glove box and than there is nothing except the stock headunit where you can take a photo off.
For placing the GromAudio interface in the console:
- just loosen all four screws of the stock head unit,
- lift the unit a little bit up (complete removing is not nescessairy)
- place the box in the empty space on the left right hand side underneath the radio INSIDE of the console
- bring back the radio at its place
- pull all screws tight
- and....done
If you don't hide the box like this, well than....you might see it lying somewhere around
Hando from the UK lexusownerclub wrote a little walkthrough with pics. If you are interested please refer to the following link
How To Install The Gromaudio Ipod Adaptor In 1st Gen Is - Lexus Owners Club
Best Regards
Sonnet