Drain hole is on the bottom, either in the middle of the skeg or behind the prop (depending on the model/year), fill hole should be above and to the right of that. I am guessing, but my guess is that is a port in the the water cooling system. The oil will be below that hole for the most part so gravity won't pull it out. Was there oil coming out of there?
For the lower unit, just pull the drain plug and see what comes out. Usually, water leaks into the lower unit, not oil leaking out since there no pressure in the lower unit so nothing to force oil out when it's sitting there. Oil is less dense than water, so if you have water in the lower unit it will come out first. Either water will come out or milk shake stuff if you have ran it lately. If it looks like regular oil you are fine.
If it's water or milk shake, pull the prop shaft and look at the gears. If it's fresh water or you catch it early you could be lucky as it takes some time for the gears to go since they are bathed in pretty heavy oil.
