Hi Ajay,
A building that is 129 years old is definitely a different kind of animal. An old building is constant maintenance, and not doing it in the same way that you would necessarily that you would with something say, 30 years old. You need to know how to handle her, as does everyone who touches her. If she's in a historic district with protections, you will have to deal with approval processes to get A LOT, if not EVERYTHING down to paint colors done. And speaking of paint, yes, you would need to have every tenant sign a lead paint addendum, aknowledging it's possible presence. If any paint is disturbed, then it must be dealt with under the assumption that lead paint is present because of the age, and must follow EPA lead paint removal guidelines which are very stringent. Neighbors pay attention and can report you and the fines are hefty. This is not to discourage you! I love old buildings, have always lived in them, but it's a different way of operating.