Since you didn't limit your inquiry to Ford wheels specifically, be aware that there are a lot of 15" and even some 14" out there, both commercial and homemade for circle track racing and street use.
Sure they're Ford wide fives and not VW? Bought the wide five spare wheel for my p/u from a guy who bought it thinking it was a VW wheel.
Or as it was explained to me if you can put your head through the hole it's a Ford. If not then it's a VW
16 x 3.5 V8-60 and 16 x 4 look the same, but the width. 16 x 5 doesn't have the short spokes. 18's have longer spokes.
Renault, DB and Panhard had 16 and 15" wide five too since some of those cars made it to the US there's a remote chance of coming accross such wheels. Matford had them in 16" also but they're Ford wheels and none were sold in the US at the time.