Well, based on carbon dating. I'm not sure I understand your second sentence. Are you stating these are fakes or there are even older ones in existence?
Let me rephrase it inshaAllah.
I understand that what so ever the old copies of AlQuraan is, Allah is not gonna us about that to enter us into Jannah!
I believe that those old copies might have written by removing "a'araab" [marking on Arabic letters, i.e., fatha, kesra, tanween, tashdeed, etc.] by those non-believers or the enemies of Allah just to confuse future generations [same as they did by adding hadith] to keep us away from the true path of Allah.
Remember! There were also lot of Munafiqs at old times. And also remember, there is NO AAYAT that supports this claim.
What we have in hand is important for us, not what old copies of AlQuraan is. I am least bother about the old copies [with or without markings] because Allah is not going to ask me about those copies. Surely, I will be questioned from what I was given, so why should I care about old copies?
Brother, hope you understand what I am trying to say inshaAllah.
May Allah increase us in knowledge and guide us to His true path