True, but it obviously can't send people beyond the nova, even if at earlier times the Library had disks of the future. But having disks of things yet to come doesn't really sound like a library any more.
On the other hand, if someone from, say, the last year of Sarpeidon sent discs linked to points from its recent past to somewhere in the more distant past … it's not clear to me that would prohibit the traveller in the far past from moving to her future/the disc's past.
This could create the Somewhere In Time
style closed-time-loop paradox about where the library's discs come from, certainly.