I have a list of all the guns in the safe along with information on each. I note whether the gun was an inheritance, a gift from a friend or purchased. I list stock and barrel measurements and note any repairs that have been made. I also provide what ammunition is appropriate due to weight, chamber length or barrel wall thickness. The rifles are treated similarly and for some I note the specific animals that were taken with that rifle.
My son values and appreciates vintage guns and he is of course free to do what he wishes with them when I'm gone. I think providing him this information will allow him to make good decisions about what to keep and what to let go.