"I'm almost certain that the cap and rod have a number stamped on the same mating side."---Pete Burton

As a large " whew , that was close" is heard escaping from Lee...

As to :
"...A lot of rod bearings don't have the oil groove."

Back when I cast my own babbit/nickel bearings I always cut a spiral groove in them... Then all of a sudden no one was driving buggies with horses...

Edit: convinced that accessing all the rod bearings probably not reasonably possible without removing engine.