I don't have a will, but I should make one. And if you have specific things you want given to specific people you should make one too.
When I was a kid I spent a lot of time with my grandparents. I loved to hear the stories from the old days and seeing the stuff they had, etc. There were a few old guns that my grand-dad had, and a couple that had belonged to my great-grandfather, that he promised to me. I was the only one in the family (other than my dad) that was very interested in that type stuff. Granddad never put that in his will, probably assuming the stuff would go to my dad. Unfortunately my dad died before my grandparents, and most of the things I really wanted went to my uncle. He's also gone now, too. His only daughter has no kids, so there's no telling where these family heirlooms are going to end up. They should keep being passed down through my kids, and theirs, etc.
I honestly don't know if anything he had would be worth anything to a collector, but they would be priceless to me. I still have the memories of the times I spent with my grandparents and that's the most important thing. I don't begrudge my uncle getting the stuff, but wish there had been provision for some of it made as well. Unfortunately, I don't have much contact with my cousin, and would feel kind of greedy asking for it now.
Even if nothing in your collection has much value to a real collector, but if you think someone might want it later, spell it out just to be safe. Or give it to them now.