The original “letterpress” printing plates used in the production of the Monthly magazine have been variously claimed to have been lost, sold, stolen or destroyed. A large number of plates from books 49 to 52 did turn up for sale online in around 2017 and perhaps others exist.
Each one is a unique “reverse image”, on a metal plate usually still attached to a wooden block and would have been used several thousand times to produce a monochrome image on a page or part-page of the magazine.
They include photographs, text, incidental cartoons and headings and several parts might be used together to produce a complete page.
In theory these can still be used to produce prints.