I have an 82 World that is a similar bike. I use it occasionally, but with all the steel chrome - including the wheels - its more of a just-sit-and-look pretty bike.
You are correct, it is noticeably heavier than the later 80s. And both wheels are nutted, making it time consuming to do fast tube changes in the field unless you swap in big wingnuts or those fancy QR nuts for nutted axles.
The brakes aren't that good. Usable, but nothing like found on newer rides. Just keep that in mind. Even swapping to higher quality pads is only going to do so much with a SP on steel wheels.
Still, for $75, if its in really good shape, it might be something nice to start off with, then keep as a backup when you decide to upgrade.