Priscilla signature on eBay?

authors sister priscilla

Maybe I don't remember well my Father Christmas Letters, or maybe I forgot something about the Tolkiens' family tree, but isn't Priscilla the author's daughter?

The second auction image does look a little odd, but the seller will hopefully explain if asked...

Here are a couple of images to compare with:

Image 1

Image 2

Priscilla is old indeed... but a daughter indeed! Here is a pictures of another autograph by her (genuine one)

Seller seems nice enough. The second signature/dedication is on a loose sheet of stationery laid in, with a third signature on the back ("Mary Dentry" he thinks) dated 1974. Sounds like "Cookie" was gathering autographs, possibly at an event of some sort. The current seller bought the book at a bookfair in 2002, so he doesn't have much provenance on it, but I think the signatures look reasonable.