Yes, you can definitely do that!
However, please note that your order will be sent out once your last pre-order item arrives at our warehouse. If you want to order both pre-order and in-stock items, we recommend placing two orders to get your in-stock items immediately. If you’re not in a rush and want to save on the shipping cost, you can add the in-stock items in the same cart with your pre-order items and we’ll ship them out together once all the items have arrived.