This was an old family copy. Based on my searching and this website, this edition is supposed to come with a slip case (on various seller listings you can find this edition with it). Mine does not.
I love the drawings by Sullivan. There’s something…macabre and slightly odd about them. Not the typical luxurious style found in Rubaiyat editions. Kind of weird. I like.
No date is given within the book, but according to this the series of Cameo Classics ran from mid 1930s to late 1940s. This Biblio entry has it at 1940. That year makes sense to me due to family history and it being before WWII (edit: for America), but it could be off by a few years.
Update 09/2023: Updated layout, added some more text, added pictures.
The info page says: “The cameo of Johann Gutenberg on the cover is from a medal produced by Anton Scharf, of Vienna, for the late Robert Hoe, from the head of the famous portrait statue of Gutenberg by the American sculptor, Ralph Goddard. Permission to use the medal was granted by the owner, William Edwin Rudge.”