Go here (
https://jlc3dp.com/3d-printing-quote) and upload your model. Please tell us the price including shipping it gives you for 150 pairs. The quality will exceed anything a typical home-gamer printer will produce.
If you are 3D printing, individual left and right hands might be cheaper than a pair joined together.
CNC routing them as you describe would need a fixture, so that all of the ten are in a known relationship to each other. It would also need repeatability, so when you turned the stock over to cut the second half, the cut lines up with the first half. That fixture in itself would have a cost. One by one in a chuck, using an oversized piece of stock, you can nearly throw the blank in any old how and be assured the end product will be OK.