Depending on the book, of course, you might not need many copies, as you said. On the other hand, it might be worthwhile to mass-produce schoolbooks and scientific texts.
Agree on schoolbooks, not so sure about "scientific texts". Even in our time, print runs of outright scientific
publications are so small as to make some of the journals prohibitively expensive even to university libraries (which leads to "publications" that, ironically, aren't really "public", and scientists working with stacks of photocopies from whenever they got the chance of making some, to the detriment of lists of references in later publications based on them; and, further down the chain of causality, online "preprint" services to cut out the middleman with the printing press ...)
They do have newspapers, so some way of printing is in use
In
our history, the first forms of the printing press were
woodblock printing and
movable type, both fraught with high fixed cost of producing (and, to an extent, storing) the master. (Sidenote: I'm rather surprised to see that
hot metal typesetting was
that late.) I'd guess that the Known World, having the info about ancient technology at hand, would rather start doing the larger priint runs with
offset technology; apart from the phototypesetting and computer typesetting variants of producing the plate, which can be replaced by
somewhat time-consuming manual work IMHO, it's still not rocket technology.
