Hmmmm,,,,, on the left side of the engine (drivers side) you can see the side
oil galley threaded plugs. I forget how many, 3 or 4 small plugs? Anyway, I would think if you were to unscrew on of those, a little
oil should be present, or even drip or run out of the galley.
By the way, there were "ribbed" and they were "smooth" blocks. The ribs were added later for additional strength. The ribs are external and were a change in the casting. Basically just some "lines" running from the top toward the bottom of the block along the sides and front area.