Charging dock connector for all handsets?

Hi,

I have an Iphone 4 purchased in Australia. At that time of purchase I got to know that there are different handsets sold around the world (although internation warrantie is claimed by Apple, it isn't true unless you got a country where they sell the same handset.

Knowing of the different handsets I now wonder whether the hardware is also different. Of particular interest is the Charging Dock Connector as I am having charging problems and am exploring options to get it fixed.

Are there different Charging dock connectors for Iphone 4 or does the single product work for ALL handsets iPhone 4 available around the world?

Thanks.