Factory Rocker Shaft Oil Holes-Vary by Year?

From post #1 : The upper shaft [shown] is for non-adjustable [stamped steel] rocker arms. These rocker arms have an oiling groove built into them. The oil holes and the square notch get pointed down and to the left of each head.

The lower shaft [shown] is for adjustable 273 rocker arms. The oil holes and the half notch get pointed toward the base of the carb.

Both types of these shafts have only one set of oiling holes. I've never seen banana grooves in any factory engine, but I never had a TA 340 either [which did come with grooves].

An old parts book might have more info.