It can mean both.
Some guys can remember things from a particular relationship since they were really into it.
So in your case,it could mean he likes you.
But again some guys have a very sharp memory so they remember a lot of things that other guys can miss out on...
Ask him about his previous relationships(obviously in a subtle manner). If he remembers particular details from his past relationships,then he might just have sharp memory. Or else then he really likes you.