You can buy the original copy of the Glorious Quran from any bookstore. The reason why the original manuscripts might be lost forever, is because as the Islamic Empire kept on expanding, copies of the Glorious Quran were produced. So official copies on paper were written down. The original ones on animal skins and bones were probably all burnt.
There exists also today many museums in Turkey, Egypt and elsewhere, where they showcase copies of the original Quran. Are they copies that go back to Caliph Uthman's times, I am not sure. But they're very old; ancient.
I hope this helps, Insha'Allah.
Take care,
Osama Abdallah