Because Firkovich is documented to have altered or misdated some manuscripts in his collection to bolster his own theories about Karaite antiquity, any object connected to him invites scrutiny, and the Leningrad Codex has received exactly that scrutiny more thoroughly than most. Unlike some of Firkovich's more doubtful attributions, the codex carries its own internal colophon, a scribal note stating it was copied and corrected by Samuel ben Jacob in Fustat, old Cairo, and completed in 1008 or 1009 CE, a date that fits comfortably with its script, Masoretic annotation style and codicological features as independently assessed by modern paleographers, largely removing it from the more general doubt attached to Firkovich's collecting practices elsewhere.
The library's custodianship today is therefore relatively uncomplicated by comparison with several other entries in this atlas: the codex's authenticity as an early eleventh century manuscript is not seriously disputed, and the controversy that does attach to the wider Firkovich Collection concerns other items and Firkovich's own scholarly claims rather than this particular manuscript's date or origin. The library preserves it as a working scholarly resource, its text underlying most modern critical editions of the Hebrew Bible.