I'm sure that somewhere in the bowels of the government we have something about the admissability of DVDs, CDs, hard disk drives, video tape, film, holographic copies (and maybe even Jefferson's device that allows a writer to produce 2 copies at one time), sound recordings, photographs, color slides, negatives, positives, etc.
Looking through the Constitution I didn't see the word "paper"? Did you?
There are a lot of words/terms not defined in the Constitution, but were understood in terms of the vernacular of the day. It is only with the current zeitgeist that people are confused.