Open the door so that you can see not only the lock side, but the hinge side as well.
Stand on the side of the doorway to which the door opens. If you have a door that opens away from you, move around so that you are next to the opened door.
Face the lock edge of the door and run your finger down the corners of the door that are to the sides of the bolt. The corner that meets the door jamb should feel like it has a slight rounding or like it has been sanded to cut off the point. If the lock edge and one side of the door are supposed to meet at a 90-degree angle, a door bevel will make that angle feel like it’s been flattened slightly. The corner on the side of the door that remains facing out when the door is closed may also be beveled, or not. You should be able to feel this on painted doors.
Move to the hinge side of the door and face the hinges so that you are facing the angle that opens up as the door opens up. Check the corner of the edge that fits into the jamb when the door closes. That should have a rounded or flattened feeling, too, although not all doors will have a bevel on that side.