Normaly the rod is numbered on the side of the rod on both sides of the split at the cap and rod.

If you are looking at a number on the bottom of the rod cap it could be the factory bearing size.

They use special bearings to get an exact tolerance. You will never be able to match that with aftermarket bearings. You would have to special order factory sized bearings if you can even do that.

Not that important. If your bearings are not to bad, just get some plasti gauge so you can see how tight they are.