Inside story (art signed by Charlie Tomsey) doesn't portray any player with #15 or who appears African American - it features Slade Cutter, Buzz Borres, Bill Ingram and Jonas Ingram - all of whom played for Navy much earlier and served in WWII. To my surprise, Navy it seems didn't have an African-American football player until Calvin Huey, who was a 1967 graduate of the Naval Academy.
The only real guess I can make is perhaps Honduran born Stephen Van Buren. After leading LSU to victory in the Orange Bowl, he was drafted by the Philadelphia Eagles with the fifth overall pick in the 1944 NFL Draft and played professionally from 1944 to 1951. He wore #15. On the other hand, he didn't have any connections to Navy.
It looks as if I may have been mistaken about the cover.