Well . . . it would be fair to say that all the new Librarians do get some training in basic library science, handling of books, management of indices, and everything from databases to index cards, plus a few extra filing systems unique to the Library itself. They have to be able to find their way around the stored books, after all. Some of them even took degrees or other qualifications in the art and knowledge of managing books and libraries before getting recruited. Others do it afterwards, while out on assignment or when stationed to some alternate world as Librarian-in-Residence, and feel all warm and fuzzy because of it.
But no, they aren’t proper librarians qua librarians. They’re mad bibliophiles who have been given the opportunity of a lifetime. Do you want to have a copy of every version of Victor Hugo that has ever been written in every possible alternate world? And the movies and musicals while you’re at it? Would you like to own an entire collection of the run of Weird Tales from a dozen different alternate worlds so that you can compare and contrast them and then write monographs about them? Perhaps you’d prefer to work on a smaller (or at least more focused) scale, and collect copies of the Tale of Genji? Or maybe you even want to get copies of the Iliad and the Odyssey from as far back as you can manage, to assemble an ultimate, definite, absolute version?
(It’s amazing what you can do when you can borrow a scanner/photocopier from a much more advanced technological alternate and then sneak into the local museum for some serious nighttime work. Just don’t get caught and burned as a witch.)
The Library can help you. The Library can let you go as deep into your obsession as you want. It will even provide unlimited shelves for you to store your loot — er, that is research materials — and let you write long monographs (or fanfics) about it, once you are a retired Librarian who is spending her or his old age in the Library. And you can make your new apprentices read them.
All you have to do is collect a few books for the Library. That’s all.
For some people, it’s all they ever wanted.