There's a fascinating snippet relating to this in the book Rise and Kill First by the Israeli national security journalist Ronen Bergman. Apparently faking passports could take months, at least in 2010 for the Mossad. Traditionally the Mossad would call off operations if they didn't have enough fake passports, but the new director decided to cut corners and reuse passports. This contributed to one of their most humiliating failures.