OKLAHOMA CITY — Considering the top-seeded Thunder’s youth and this roster’s relative postseason inexperience, Paycom Center boasts nothing short of a seasoned second-round environment. There are vestiges of playoffs past anywhere you look — a white Kevin Durant jersey spotted during an afternoon walk through Scissortail Park, the piped fence around a parking lot between 2nd Street and Hudson Avenue has rusted over plenty of its Thunder blue paint. This crowd’s been coordinating their free T-shirts for 11 of the past 15 playoffs, and they jeered Luka Donu010diu0107 all Thursday evening as if it was second nature.