There is no “fossil record” of ERV’s or Vitamin C Synthase, unless you count the ‘fossilized’ insertion of a retrovirus genome into a common ancestor as being part of the ‘fossil record’. I don’t know anyone else that does.
Still, I will give your questions the due dilligence that they deserve. I may come up empty on this one, but I want to know what is known on the subject nonetheless.
BTW, thanks for asking such excellent questions.
You still there, Allmendream? If you are, I have a few comments and questions re: Vitamin C Synthase and ERVs.