It's amazing how much variation there is among utilities in their construction standards, as contrasted with work on the customer side of the meter.
For example, in my area (Dominion Virginia Power territory), there seems to be no effort to identify phases on distribution lines or to keep them in the same positions on the pole. It's common to see primary conductor positions interchanged where the line turns a corner. Linemen refer to wires only by their relative locations on the crossarm at a given point: "road phase", "center phase" and "field phase". Even on service drops from aerial three-phase transformer banks, I don't see any phsae identification. It appears that phase rotation is only established when connection is made to the cuttomer's service wires.
In contrast, PEPCO, the neighboring utility to the north (serving DC and its Maryland suburbs), seems to identify phase positions consistently on its primary lines. On certain poles I see wooden placards with nailed-on metal letters "A", "B" and "C", which I assume are phase labels. I haven't looked closely at PEPCO's construction so I don't know how the identification is carried through the primary and secondary lines.
