it seems like guys that could make a pyramid,, could make a caul,,if need be,,
yes of course maybe they didnt,, but it does not seem that impossible to me,,
or dig a pit and heat it like an oven,, with the caul on it,, if they wanted,, I am just guessing,, but doesnt seem out of the realm of possibility,, I am not worried,, my osage bow is immune to moisture,, and I am not that into heat treating,, I have a great plum bow ,, made by one of the best bowyers in the world,,it was not heat treated,, and I think it shoots amazing,,,