Most every bearing manufacturer has the correct grade of bearing, which is on the bearing as a letter code before or after the number - bearings with just the numbers are unlikely to be the correct grade.
Which includes OEM and most of the proprietary kits like Moose , All balls and Pyramid.
But the suffix is not universal , sometimes X OR J , or both .
Bmw and Guzzi used the same bearings, and Mazda as wheel bearings in the FWD cars , so a search on these might give you a better grade of bearing.
IMHO bearings are best bought over the counter from a bearing specialist who will advise on the correct grade.
He will also stock the correct grease, probably Timken brand but it will be Extreme Pressure, EP for short, and waterproof .
They will last longer if they are preloaded correctly too, the aim is to have around 1 thousand of an inch preload when the bearing is in a unloaded condition, which helps to keep the rollers in the correct alignment.
Not hard to do initially when you are re assembling the forks, but they will bed in and need readjustment after a few hundred KM.
Manual says just remove all play, but you probably want just a little more than that.
It is a bit of a learned skill, the mechanic at my fav dealer/cafe/ servo has that skill and I just give him the $60- and he gets it just the way I like it, first time, every time!