Yes, you can, we accept any PCB shape,sure about the PCB with a non-rectangular shape.
Note that a rectangular outline (the minimum rectangular shape which can cover the entire PCB) will be used to calculate the board size. The shape should be clearly indicated in at least one of your copper layers. Otherwise you must supply a mechanical plan, separate from the Gerber file, indicating the shape of the PCB. This file has to have a reference to the copper layers, or has to have the same offset as the other layers.
Posted in: PCB Specification