This exactly. I haven't removed the housing yet, but from everything I understand, modern housing won't work. I can find some on ebay that claims to be a correct replacement, but I would be buying enough to do about 20 bikes. I guess I was hoping for some sort of experience based indication of "x, y, and z conditions are fine, reuse; a, b, or c condition means suck it up, buy the long roll of housing and plan to store it properly for a long time."

I'll probably try to reuse, unless someone chimes in with the "suck it up" conditions to check for. Thanks also to Velo Mule for detailed description of lubing it up. I would probably just have used a dry chain lube with is what my LBS has always advised for brake and shifter cables.