Answer:
Personally, no, I don´t think it should be repaired, as long as it is able to be walked in, and non-dangerously approached. I think this because, with historic buildings, it is better to see them how they were originally presented. But, if they are worn down to a point where the building is no longer there, or, unsafe to be in, then it should be entirely repaired as accurately as possible.
Explanation: Hope this helps..