Easiest to put the marks at the back with the flathead-looking slots aligned with the floor. That's how my old bars came out and my PST bars went in.

1967 Dodge Coronet Deluxe station wagon

1.03" T-bars, QA1 arms/rods, Cordoba/GM Metric/Volare brake & knuckle, XHDs, Hellwig rear sway, 318 Magnum w/ air gap, 727, 3.23s