I agree with LightningBoldtz. The flavorizer bars are usually the first thing to take a hit as they are the only thing standing between the food and the fire (besides the cooking grate of course). However; I agree with what you're saying, for a brand new grill fresh put of the box for only a single week, that definitely looks excessive. It almost appears like it is starting to rust at the top end of that one flavorizer bar?
Your grill is an S-330 so those pieces should be stainless steel. It definitely shouldn't look like that after one week. I have a Summit S-670 that I bought brand new in Jan. 2013 and my flavorizer bars don't look anything like that after 2 years and 100+ cooks on it. You should call Weber and talk to them.
Send them the pictures you posted. Weber offers a very good warranty on all their products. Your serial number on the grill should prove that it's nearly new and I'll bet they will send you some new bars. As far as cleaning them regularly, I use a flat edge scraper to scrape off any baked on crud. It's impossible to get them "new looking" after they have been used, so I wouldn't even attempt to try and make them look clean as new. I have strongly suspected for a while now that Weber is sourcing a lot of their parts from China, even though they claim they are made in the USA. I think a lot of the individual parts are coming from Asia and being sent here to be assembled. I know that steel from Asia isn't nearly as strong as American steel and rusts and corrodes much sooner. Maybe that's what happening here? IDK? Good luck.