My flight this past Sunday from DAB-ATL was on a DC-9-50 It had WiFi and I was glad to be on the 2 person side, in the exit row. There was some smudges on the ceiling, and a couple places where the interior was showing wear, but I'm pretty sure that the majority of the folks on board didn't notice or care that it wasn't a MD-88. I tried to spot the data plate in the door area, but couldn't

I'll look again when I'm on one this coming Friday night.