Even so, if Spock's even vaguely as legendary as Kirk in the 24th century the fact that he served on the Enterprise is probably common knowledge.
Additionally, Nero's ship would still have a 24th Century database, though granted I have no idea what that might have to say about Spock. It had holographic images of him as an ambassador though, which suggests more information would be available.
Why would Kirk and Spock be legendary to the Romulans?
It's really why the story just doesn't hold together... you have to make to many "leaps of logic" to make it work. Why would Romulan miners have any knowledge of Starfleet officers who hadn't served for a century? The Romulan Empire has always been presented as a closed society akin to North Korea.
The holgraphic images are probably from the visual communication just prior to them entering the rift.