Yes, but Michael didn't know that.
The only reason Michael would have had for asking Fredo to arrange the evening's entertainment would be if he knew Fredo had been to Cuba before and expected him to know what to do. Fredo had been working casinos since the days of Moe Green and would have had many opportunities to go before. Michael just didn't know that Fredo had hooked up with Ola on one of his previous trips.
So, why does Fredo ask if he knows anyone in Havana? There's nothing in the novel or films to indicate that Fredo had ever been to Cuba before.
From Fredo's dialogue it seemed to me that he was never in Cuba before. Also after some thought, it seems to me, that Mike asked Fredo to show the government people a good time, just to keep him busy and out of the way, plus as Fredo said "it was his speciality"
