Many of the USGI rifles we have in our hands and in our vaults are 100 percent original. Sure its fun to have the money and time to throw parts at GI issue rifle to make it fit in our dream of an "original rifle".
They are only original once, and each part that is replaced, chips away at the rifles history, and deep inside, you know, someone will someday pass it off as completely original. For money. You may think you will live forever, but the reality is, that rifle will outlive you. It may be sold for a hundred bucks after you are gone, and it may have made you very happy. With that Rumanian flip sight that was made so carefully to fool the experts.