Probably a Fidelisto. My friend said the city of Miami, maybe Miami Beach, lent the Harleys to Havana as a courtesy for the police to use during the races but were never returned.
The motorcycle cop photo might be later than 1958. A friend of mine who was born in Cuba and lived there through the revolution said that immediately after Fidel took power many men(regardless of prior affiliation) grew beards to outwardly affirm loyalty to the new government. Crazy times.
Shelby with bare arms and in bib overalls....what you don't see is that the mechanic dumping the can is probably smoking.....