Those look like car tires. Quite worn-down (flat) in the center. That would suggest previous owner hardly ever got the bike leaned over, or did a TON of highway riding. Finish off the season (careful on colder pavement) and replace for spring. You'll love new ROUND tires.
When buying new tires, consider what you'll be doing with the bike. Dual Compound touring tire would be best with a harder compound down the center to help prolong the life of the tire over lots of highway and mostly 'upright' riding.