Nope, not wet plates. They used to add clouds in from separate cloud negatives. You might need to go back to the daguerreotype to find something that wasn't manipulated! I'm not putting money on that, though.
I had never really thought about this, but I guess the daguerreotype is the only form of photography with complete integrity.
“The contemplation of things as they are, without error or confusion, without substitution or imposture, is in itself a nobler thing than a whole harvest of invention”