Depends entirely on the case and it's layout. For instance in the BitFenix Prodigy it was very common to mount a Noctua NH-D14 and have no rear exhaust fan at all because the cooler to case clearance was about 10mm. The cooler itself acting as a rear exhaust fan.
With some layouts, especially amd, the cooler often faced straight up, not to the rear, so a rear fan was useless and top fans far better suited.
But generally with any tower type cooler, yes, you'll want it facing the rear and have a rear exhaust.