Dave,
I thought about using a product like Waxoyl to coat the insides but installed them as-is since I trust them to outlast me. I think the cost was bout $2300-2500 then, complete with new picture frame. (May have included a new cow catcher - bonnet frame - too).
When handling the rails I could hear much rust trying to sound like a didgeri-doo aka one of those rain forest instruments in the square members. A closer look at the members will show where the tubes were brazed (the gold color) and where the pinhole rust is coming thru the outside (the black tarnish). The rusty brown color on the end of the top photo is where some of the dipping solution drained out the end. Just south of there is the clearest example of an active tin worm.
Regards,