It'd be a lot of work and I suspect it could be done for a bit of profit but obviously not as much as they'd get if they didn't have to do it.
The quality of the film is something else entirely and depends on how well it's been stored and kept over the last 20 years or so. If it's beat-up to much even more work would have to be done to restore it.
Any "3D" however would just look shitty. It "can" be done but since it wasn't originally filmed
in 3D there's a thick line between "looking good" and "looking like shit."
James Cameron wants to do Titanic and Terminator 2 in 3D and will likely sink a lot of money into pulling it off well, I've got faith in him for that.
But for a 20 year old TV series on a limited budget for a DVD release? It's going to look like someone playing colorforms on the lenses of your 3D glasses.