OneWire in Due

Yes, it's possible to use git to obtain the source from any point in Arduino's history. You'll only get the source code, so you'll need to build it yourself (easy on Linux & Mac, requires setting up lots of stuff for Windows).

I'm not an expert with git & github. You'll need to look for info online (there is a lot of info on may sites), or find someone who's more knowledgeable about git to help you.