There were 2 things with the iPhone 3G:
1) They warmed the color temperature of the displays compared to the original iPhones. Apple said the original was too blue. This upset some people who liked the original, but it's not gonna change. It'll be the same color on these phones.
2) At the same time there was a factory problem where some sreens (a small number) were actually pretty yellow. In those cases Apple would exchange the phone. That issue was fixed and I haven't heard of anyone getting a new phone with that problem in a long time.
Due to both things happening at the same time, people got confused when talking about them. It's still kind of confusing. I don't know which issue the OP is talking about, actually!