I certainly could be wrong. I just figure most folks forging and finishing a damascus knife will put their mark on it. Or if they bought some Damascus billets from someone else’s forge and did the grinding, they’d mark it. Neither are small feats so the makers want others to know who made it. There’s not much point in a sterile custom knife, though I’m sure one exists somewhere.
If your stepson is still alive, you can ask him the name of the knife maker.