Do all iPhone 4's have the "death grip"?

Yes, the "death grip" is actually a physical abnormality that occurs when the human body touches the antenna on the bottom left strip on the front of the phone. Apple said the best way to prevent signal loss is to use a case, Steve Jobs said and I quote, "Don't hold it that way...". Best option just wait until the next iPhone comes out in the summer.

You should avoid touching the metal strips on the side. They are the antenna receptors.