Lost in the South

The front brakes on my 85 Carrera drag slightly on the rotors. I know that's a classic sign of needing a caliper rebuild but I also know that old (rubber) brake lines will swell on the inside making it harder for the pistons to return. I am wondering if anyone has had success alleviating this problem by simply replacing the lines before going for the full rebuild.

Any other thoughts on how to address this issue?