I have purchased from the following and been happy with the transactions. No issues or concerns with authenticity to date.
- Prop Store
- Production Treasures
- Heritage Auctions
- Julien’s Auctions
- The Prop Gallery
- Prop Masters
As always, you should ask questions and do your own research. One thing I have found, is the descriptions, especially in auction catalogs are not always accurate. Not saying the item is not authentic but auction houses often get details wrong… was item used in the original film or the sequel? The materials the item is made from… is it a hero piece or a background item… I’ve seen mistakes in all of those descriptions.