I don't know the answer to this, but I suspect I know the answer: does Hilary's printed email dump (which is all that she will provide) include the email headers and associated metadata that comes with an electronic copy of an email?
I rather doubt that she has; but, I ask because she claims that she has fulfilled her obligation by providing printed versions of the emails. So, even if we were willing to concede that incredibly dubious claim, has she really complied with the law by not providing the entire electronic record?
Obviously, this part of the email can be quite important (just ask the NSA), so if she isn't providing that, what is her justification for not doing so?
If the law doesn't specifically make an exemption for that, then it can't be omitted. When she received an email, the header is a part of the email that she received. Therefore, it is part of the official record.