no, they're all the same - the circle should be a little ball stuck to the flywheel - the lines may be to help w/ advance or retard, but correct timing is when the ball is visible at the pointer w/ a timing light - to find TDC remove #1 plug, put a finger over the hole, and crank until you feel compression then go just enuff further to line the ball up - if you've got the valve cover off, crank until #1 intake is closed, then a bit further to line up the ball
Bill
