For what looks are worth, if you compare the photos on Rockauto, the Motorcraft, Gates, AC Delco, and Four Seasons tensioners all look the same. Dayco and Continental are a little different.
My only experience has been with GM, but I ordered a Gates kit recently (Belt, Tensioner, and Idler) because the parts looked exactly like the AC Delcos online. Both OEM and Gates pieces were made in Canada, and both idlers had bearings marked "NTN Canada." The new belt was made in Mexico. The Gates A/C tensioner also looked identical to OEM.
The original parts with 108k miles are still in good enough shape to keep as spares. I replaced them because the pulleys were a little rough and I figured the belt was due after 15 years. The engine is a lot quieter now.