It's only original once blah blah blah...
For my '71 Trail Blazer (see the thread in this section) I am going for N.O.S parts. I am doing that more for me, so that I know that my bike has the correct period pieces. I could care less about re-sale value, or what others may say.
And no matter what I (we) do, there will always be someone saying that "hmmm, that's the wrong colour flux capacitor you have there. Those were only made between 54-58 and the tank colour is a shade off, and have you changed...etc etc"
So, go NOS, but do it because you want to, not for others.
And Lucas? I say sure why not? You have your new ride for reliability etc, this is a project, so have some fun with it.