First Q: How long ago was the work done?
Second Q: How's the quality of work?
Third Q: Do you think was done up to Code?
Assuming that you answered: "Long Time", "Good", and "Probably", then I would ask:
Fourth Q: Who's going to tell the County?
Assuming that 1 thru 3 were negative: I wouldn't purchase the house; it could be a Pandora's Box.
Good luck and may God bless