Vintage Tiffany large Crown Key oval necklace sterling silver

This is an authentic Tiffany necklace- see pictures. It is rare and I think the 24” oval link chain is more preferable than the newer beaded one. This necklace is going for between $350-450 usd on EBay. I do not have the original box. This would be a great gift for someone, or treat yourself! I have included 2 metal test pics showing the silver content of the pendant and the necklace known as ag.. We are business owners and can verify this upon request. We value accountability and integrity. Susan