“Dexter” and “Homeland” set series ratings records in their respective season finales Sunday night on Showtime.The Michael C. Hall starrer drew 2.7 million for its 9 p.m. showing and 3.4 million over two telecasts. The season-seven finale was up 24% versus last year’s season-six finale. As for “Homeland,” the 10 p.m. telecast garnered 2.3 million and an additional 400,000 for a repeat telecast later in the night. Series stars Claire Danes, Damian Lewis and Mandy Patinkin. Both shows set records a week ago and were up in season averages from 2011. Each will return to the pay cabler in 2013.