Chances are is that somebody broke a ring trying to get it on the piston and sold the rest to you. The best you can do is check the ring gap via the cylinder size. Stick the ring in the cylinder, turn the desired piston upside down, and push the ring so that it sits level in the cylinder. Get some feeler blades out and check that gap that is left in the ring. Compare that to what it should be. When I have to blueprint a motor, I always do this to be sure the gap in the ring is within specs. If the gap is too small, then it will need to be filed. If it is too large, then you are screwed, unless you like low compression and blow-by. Buy a new set of rings by the same brand so if you break one, you have extras. Chances are that you will stick that piston in the cylinder and it will not develop good compression seeing that you have no idea what happened to the motor that they came out of.