It is possible he does not know the correct year of his engine. Perhaps he has a 1973 65hp which is a hydro mechanical shift. If the engine has two control cables, it is a mechanical shift. If there is only one cable, it is an electric shift.
On the other hand, I am kind of fond of the 1972 65hp models. These engines did indeed have the hyrdro-electric shift gearcase, but they also had the simple/reliable mag-flash (magCD) ignition. The hydro electric shift gearcases are pretty reliable, no real internal issues unless water gets inside. But yes, you would have to ensure that the control box wiring/harness/shift switch are in good shape.