Is there a difference between maverick center caps & Rancho or other Ford center caps for the same time frame?
I don't think so. There are two different red ones. The crest is slightly different. A torino of the same time period should work for you.
None. No '71 maverick ever came with Magnum 500s. The caps on the right of that photo would be what '71 Torinos had, and later-model Mavericks with Magnums.