72 Cuda manual drums. I purchased this car with the brake system OPEN. Meaning no MC, flex lines missing, etc. All the metal lines are there and was wondering if I should change them out or salvage these?? Unknown how long they were open.

I'd use them. I'd just run fluid through them. See if any junk comes out. Blow them out with a compressor and then hook up the new brake components.

I'm as cheap as the next guy (ask my wife ) but when it comes to brakes I would just replace the lines. Chances are that there is nothing wrong, but I don't like to take chances on the brakes.