shimmers

Has anyone noticed that the finish of the wheels on the GS430 seem different over the last few months? My GS430 is from April of this year. When I was at my dealer the other day, I took a look at the test drive vehicle, which is from January, and the wheels were noticeably darker. Looking at the wheels together, I noticed that my wheels were much shinier, more silver while the test vehicle wheels were more darker, with a rougher - speckled finish. Out of curiosity, I wiped the test car wheels and even polished it, but still different.

Is this related to the wheel porosity problem? Maybe in March / April Lexus started shipping wheels with different, better finishes? Or does all wheels get like that after a few months? If so, I'm not looking forward to my wheels looking so much daker in a few months...