As long as they aren't on the DNC - they are fair game (unless MA / MAPD )
That is why I said, Odds are, you can't legally call them.
I think over 80% of consumer phone numbers are on the DNC. The other 20% don't have phones plugged into them, they just have the line because the cable company gives them a better price for their cable if they keep the phone line.
There are still 5 people left that are not on the DNC and have a working phone, so you might have one of those.