OH just had a though....our rams are 5 x 5.5 bolt pattern. The older (I think pre 1998) F150's were 5 x 5.5 bolt pattern. They had a oem wheel that is very similar to these, don't know the diameter though, but maybe you could look into it....they look like this:
I have a feeling being older they are only 15" in size though. Anyway, I once got a set for my F100 for like $50 from a junkyard, then later found out the F100 did not share the same pattern as the F150....that's how I know lol.