Wouldn't something from that period be written with seal script? That script looks like modern Han characters with an archaic font - it's completely readable.
A far as paper writing, I found [1] which said roughly 100 A.D. some paper production began.
[1]: http://www.chinaheritagequarterly.org/tien-hsia.php?searchte...
Looks like they were using colour as variable/labels.