I believe the answer should yes They all use the same 30 pin connector. Having said that... some connectors give me issues with power on certain devices.. so I am not sure that ALL connectors from Apple will work with all Apple devices using a 30 pin.
They usually do, but as an example... the 3rd party (Belkin) connector I was using in my car worked perfectly with my 3Gs iPhone... but kept telling me it was no good for use with my 4g iPhone.
I haven't bothered to check, but I'm guessing the voltage or something changed,
Put another way... no connector has ever done any damage.. they just say they are not working.. and then they actually do work....
That is when they say they aren't working.. usually it's no problem at all.