I am suggesting that there is more to proper ID than the size description on the bearing. I know of some of the differences but I can't tell you where they matter or when they apply.
I know that if you get that SKF bearing in a MB box it will be fully described.
You have picked one part to do this expose on and you are probably right in this case. I buy nuts and bolts and bulbs from many vendors. The only time I get significantly better deals on small quantities is if I buy lesser quality or "unknown" quality.
But I always buy in long term volume that keeps me from paying "Matrix" pricing.
Bosch Master, ASE Master, L1
33 years MB technician