It is indeed true that the bearings used in most helicopter gearboxes are manufactured by a vendor like SKF or Timken. But the bearings are made to a detailed specification supplied by the OEM.
The particular type of planet gear bearing shown in the example above is quite common with helicopter gearbox epicyclic stages. But one problem with these epicyclic stages that use more than 3 planet gears is their capability to evenly share loads between the planet gears. With the example of the EC225 output stage that used 8 planet gears, the load mismatch between the planet gears/bearings could be up to +/-25%. And the fatigue analysis for these planet gears/bearings would need to take this into account.