I think not. If you took apart an iphone 3gs from launch day and one made last month, I bet you they are EXACTLY the same. If Apple tries to change a part or redesign any part of this phone especially the antenna, and some site like ifixit finds out.....you can imagine the excrement storm that it would cause after holding a press conference and saying that there is not a problem with the design of the phone.
Ill say it again, they are not redesigning this phone. Period. They are selling them far and away faster than they can build them, the vast majority of owners are totally satisfied, and aside from upping the storage capacity and dropping the price of the original iphone, they release new phones YEARLY.