My recommendation with any firearm is to only buy a gun that you're happy with the condition as it exists right now. It's rare that a project is a money saving proposition in the long run, and it's really, REALLY easy to end up with a safe full of half done projects that still don't do what you want them to do.
I could be tempted to get an incomplete firearm if it was something I really wanted for collecting purposes and the price was right, but it would have to be something so unusual or rare that I'd be fine with it if I never got the parts for it.
