Someone on CCF (I wish I remembered who) told me the easiest way to determine OBV. varieties and it's all in the forehead. The Charlton tells you to look at the ears, lips and chin and on midgrade coins like this, without an untrained eye you can be looking all day. Trust me, I did lol. The obv 4 has a flat forehead from the hairline to the bridge of the nose with a small valley in the middle. The obv 5 stays almost parallel with the "EI" near the hairline and is rounded to the bridge of the nose, as yours is.