The bearings were "staked" with those little punch marks. This is a technique used to hold the bearings from moving. It might be just there because the owner thought it could help, or it could mean that the bearings had been driven out cold, and may have a loose bearing seat. Probably/hopefully, that is not the situation, and it was just an extra safety measure he did.
Those are some top grade brass caged bearings in there now. They are the best you can get. We always use brass caged bearings for mains.
Heat that case to about 250-300 degrees F to release the hold of the case on the bearings, and then drive them out with a punch or a wooden dowel. When the case is hot, they come out pretty easily. Never drive them out cold, and never try to press them in with the cases cold. Always heat the cases for bearing changes.
So, what happened to this engine that it has damage and needs rebuilding, after it was obviously rebuilt by someone previously?