My father loved collecting Canadian antiquities, and there is even a WW1 medal among the items. He learned very quickly about sellers remorse, tho not from the seller but rather their kids who had NEVER shown an interest in the items until they were told they were sold. Then the seller would call, sheepishly asking for them back.
From this he learned to always document where and who everything came from and get a bill of sale.  When he passed away, his obit wasn't two days old before my mother began getting calls asking for items back, one person even suggesting their item was stolen.  We simply went to his big binder of receipts and read off the date and name of the seller, and never heard from these people again.

An inscribed medal is a silly thing to try to steal and fence - after all it has the owner's name on it! I think it's everyone's assumption that Grandad would never get rid of his medals/family heirlooms, but 99% of the time that is wrong.  What we value changes with time.