Proof these sheet music pages existed?

Came about these sheet pages of Beethoven, Clementi and Mozart

Can anyone find if they existence?/got sold?

Finding the company uemusic/universal edition is easy enough, but i cant find that they ever sold the white sheets, let alone anything about the red book with mozart

Thanks in advance

https://sh.itjust.works/pictrs/image/c07d6026-7710-426a-a12f-dc9cd698c4c1.jpeghttps://sh.itjust.works/pictrs/image/124db2cb-28a1-4b30-8fbd-8495bddfb96c.jpeghttps://sh.itjust.works/pictrs/image/b1d7d354-0c81-4683-9da9-b7a096f163c7.jpeg