My most recent treasures are two signed copies of Nibbles and Me and a very interesting presentation poster type thing with a signed album page that someone went to a whole lot of work to create.
Same here. Both books are superb - I like the second most of all for its early style, condition and content. I might guess the second one you have shown was signed closer to 1946, and the other book closer tom 1948 or so.
I do have a dust jacket - it was on the one signed by Sara - so I just swapped it to the one with the full signature - and it is in pretty good condition.