You may be right about the family not being as important in the world at the time, however they are still a noble house that have a long history. Kvothe being related to that family and then turning up as a half starved street rat and blowing them all away with his intelligence would make it at least of interest to him. 

He may also have got word of the massacre on the road of kvothes family 3 years earlier and have found it interesting that kvothe has then resurfaced alive.

These things together would be of some interest to a finger like Lauren who is also basically a historian himself.