Answer: I think the trees are likely to produce fruit, but they need to be mature enough to do so. How long that might take depends upon the tree. You didn't say whether or not the trees are flowering. If so, and they aren't producing fruit, it's because they need a second (different) apple tree for cross-pollination. If they are not yet flowering, they simply aren't mature enough yet.
Best wishes with your apple trees.
Q&A Library Searching Tips