Leopard geckos are nocturnal so they do not need the uva/uvb lighting. You can still put a neon for the beauty of it. I put normal desktop lights over the hot spot (at the same place my heatpad is) to make the temp higher for certain period of the year. Of course if your hot spot isn't hot enough (85 to 92) then you should have a small light over there to increse your temp.
So it's up to you, you can use your neon but it won't give any heat. It does make your enclosure look better, but again not necessary.