Briggs piston rings replacement: Received the piston rings for a B&S 5hp. The top and middle rings both have only one paint stripe. I have looked very closely and cannot determine which one is the middle ring. Each ring has a inside beveled corner. The bevels however are on opposite sides so that when placed together both bevels are to the inside or to the outside. One bevel is slightly bigger than the other. Also, when placed together - paint stripes to the right - one paint stripe is closer to the opening by the width of a paint stripe. Don\'t know if that helps any. Could it be that I have two top rings and no center ring?