You should see the “Hand Mesh” in place of your controllers, however if they are not tracking it all then the “HandMesh” will appear attached to the root component of the VR character at the feet. First check with in the VR character blue print or the motion controller blue print for something along the Set motion source node. If the controllers are not tracking then you will have an issue seeing them in game. Docs here: https://docs.unrealengine.com/en-US/BlueprintAPI/MotionController/MagicLeap/SetMotionSourceforHand/index.html
Another way to check would to play a preview of the game in any mode, and use F8 to eject from the pawn and try to find them in the world browser, once you have located them at run time you see if they are even spawning at all, are invisible, or spawning in a weird place.