Oh... Ok so the signing time on the darknet paper could easily have been faked too. All you'd need to do is set your system clock.
Seems that way. OP said this:
"Now normally you would use a Timestamp Authority (TSA) to validate your system time. There are enough public, free, RFC 3161 compatible TSAs that this is not a difficult thing."
So failing that you can just change your system time.