That is a good idea to make an inventory with values, be sure to date it too. Take good pictures of the item. Put it it with your will and important papers.
I was an Antiques Appraiser and ran Estate Sales. I can tell you many stories about families who didn't care or maybe didn't know what they were having me sell. When I found things that were marked, (which were few) I always asked if it was something they wanted to keep because the owner cared enough to mark it.