So, if he really, really, reallllllllly wanted me to do this, you'd think he'd at least be on the phone discussing it. As such, it seems I don't have a trustworthy directive of what to do with them. So, in my safe they'll sit (excepting maybe the occasional trip to the range - you know...to make sure they're still functioning properly.
Good decision. Don't bring up the subject with either your son or ex: Maybe it will go away.