The mark is to the right of the deten tab that locks the dist cap into the correct place .
Look at the circumference rim of dist housing, where the cap would sit .You will see a notch on the top of that rim..it is faint, so a little scaping w/razor blade will make it more evident ..that notch/line is @ #1 plug wire tower of cap , when cap is installed...start counting the wires from that point. according to the firing order.

__________________
A Dalton