no, you cannot replace 1g dock with 3g. connection is completely different. instead, you need to swap the whole midboard... it is possible to swap just the dock connector, but that is EXTREMELY delicate operation. i strongly recommend you, to buy the assemmbly. you will save a whole !&^@ of problems... unfortunaltely, you cannot buy it on iFixIt eshop, it is unavailable... try later, or search different supplyier.
I have the same problem! I'm buying that piece Dock Connector, but I see that has a battery to one side. and seeing the piece says that does not take the microphone included. I'm in doubt, because I only see a small battery in the connector Dock Connector.this is the part that you say?
Charging Charger port flex ribbon for iphone 2G
I repair the iphone 1st gen and that model ONLY.
I have used but tested dock connectors, also the assembly which is less messy. but i am not sure if i can supply my email here or not.
It is Not a battery to the side, it is the home button connector and actuator.