I used to also have my doubts about whether the stones were real - all I can say is that in MY personal experience, I have attempted no less than 20 Liver Flushes because I have a very congested liver and a lot of problems. I have only had a couple of stones on 2-3 occasions and all the other times I have not a single stone. So the olive oil is definitely not congealing inside me to produce anything resembling stones... So for me this kind of supports the idea of the stones being real. Otherwise why didn't the gallons of oil I drank turn into stones?
What's more, the first time I ever had some stones come out (about 20 stones) was when I did an egg yolk flush - the stones were the same green colour despite not using olive oil.