potential fz1 buyer - a good old rotor question

[Torqfazer]

Hi. did a search so im pretty certain this is a first for this question.


So say im going to buy a bike and in its past the magnets flew in the rotor and lets say it was apparently fixed.


first question is
re there any potential pitfalls here?


second
any obvious 'tells' that it happened at all?


cheers