Funny, the first thought I had was that you thought you could get HD signals from an ordinary laserdisc. My second thought was asking about ripping MUSE discs. This is only about upscaling, how dissapointing.
Upscaling to 1080p usually doesn’t magically add data that wasn’t there in the first place. Bonus points if the laserdisc was taken from a tv show that was recorded on (standard definition) tape, not film. In that case there wouldn’t be practically any additional detail to begin with. There is, of course, the “super resolution” algorithm which helps (for filmed or HD sources brought down to SD), but I’m not sure by how much.