The two lines towards the top (crown) of your piston ARE the rings. They will have a slightly different color than the piston itself, unless of course the engine has gotten so hot that the exhaust side of the piston is burnt. In which case, everything will be one blackened mess, sometimes with 2 telltale silver stripes where the rings still try to touch the cylinder wall.
Are you having running problems? A good look into the exhaust port will give you an idea of what the top end is like, but I'd pull the head for a closer examination if something seems suspect.