Well, the only one you have to spoof to incriminate is already redacted, so there's not really a 'spoof' concern to worry about unless that is unredacted.
Receiving such an email doesn't have to be a spoof. See typical spam folder of anyone for all sorts of crazy implications about the recipient.
However, the date is more reliable and back in 2014, nearly no one would be motivated to fake that sort of email toward Epstein. That was before his whole situation was popularly known. The people aware of it were largely in on it that early on.