I have an '11 Ranger and my wheels are 15". Had an '03 Edge and the wheels on that were 15's. I also had an '01 and THAT had 15's too. All my Rangers were extended cabs or 4 doors so maybe that's why they had 15's.
My point being, just because the one's you looked at weren't 16's doesnt make them non-Ranger wheels..jmo.
Here's a pic of my current Ranger, an '11.
CIMG1697.jpg