brake line opinion

I would replace them. In the grand scheme, those line are pretty cheap.
Brake fluids absorbs moisture. The outside of the lines may look fine but you can't see the inside. How much time, money and hassle will you go through if a piece of rust cuts loose and causes a leaky seal? How much time, money and hassle (and more) will you go through if a brake line ruptures due to a thin spot caused by the rust.
Replace them; drive and stop with confidence!
C