I have a 2000 E320 with a Java interior, which is the combination of dark brown and beige. The beige (glove box and adjacent panel strips) seems to be yellowing slightly. I only used 303 protectant since new. Otherwise it is in perfect condition, but if you compare the color of this area with the color under the steering wheel (where sun doesn't get to it), you can easily see the difference. It's the difference between a nice clean beige and ... well... a hint of yellowed beige. Never been any smoker in the car.

 

Can you post a picture?

 

I could but you couldn't see it. Its just a slight differing in tint. It's just enough to be noticeable but it's clearly there.