If you can color match, probably.
Rumor has it that Cardinal Richelieu's men had ways to read wax sealed documents.
How many of these documents have multiple layers of meaning embedded in them? Steganography, euphemisms, inside jokes, shibboleths, what have you. I wonder how many things these letters say that we simply cannot read.
If there are other pieces of paper held in the wax like a 3D matrix of sorts, it gets much more difficult to undo then redo the seal.