I agree with you, John. As others have mentioned, companies that have developed legacy products must have some level of documentation on the design and manufacturing processes at minimum. I think that it may be worthwhile to compare their level of documentation with a DHF to identify gaps, but I think if the gaps are small and the history of the product usage has been favorable over a relatively long period of time, it may not be worthwhile to initiate more paperwork (as it would simply just cost the company resource and therefore money, when it already has actually demonstrated the quality of the product).