Yamaha went with a non-replaceable bearing for a while, particularly on the 4 strokes, they also had thinner bearings. If you've heard, the 'delamination' issue was with the newer thin non-replaceable bearing wheels. They have since decided to go back to replaceable but I haven't done enough research to know if it's the old bearing width or the skinny one. The original move was likely due to cost if I were to guess.
It boils down to this, if it's got a c-clip, it's replaceable.