Well if they weren't shot with a HD camera, it's kind of defeats the purpose. I mean, if you're watching a program that was shot with a standard, old camera, then just because it's on blu-ray doesn't mean it's going to look any better. But maybe i'm missing something or wrong.
It depends. If the shows were recorded onto film then it is possible to convert them to Blu Ray since film is high def, much higher than Blu actually. That's how they have released old movies on Blu. If they were recorded onto tape, which is probably more likely for TV shows since it's cheaper, then there's no way to convert them to HD and Blu Ray would be pointless.