Of course, I cannot speculate on how your situation may turn out. But once upon a time my wife and I were in F (row 2) on a 757 which changed to a 3-class 767. Our seat assignments remained but we were now in F on a 3-class. A few days before departure we were moved up a row (bulkhead) per ual.com. I realized after boarding that two sky marshals were in row 2. Anyway, I did online check-in and we stayed in F.