OMC Sea Drive (1987) Lower Assembly

[seachest]

Hi folks - You have been an imense help to me yet again - I found a bunch of through the "Pan" fittings that were potential sources of sea water - all siliconed, loose factory plugs replaced (with bail plugs) and a new gasket between the cowling and pan - hopefully, I will be posting the picture of the area in question (I can't find my service manual so again I'm tapping your vast knowledge base) - In the picture, above the prop, there is a "fin" - This is where the zinc is attached and there are 6-8 bolts securing it to the main shaft - Q is "Is there supposed to be a gasket between the two pieces ? I have noticed that when I raise the O/B alot of water drains out between the two. I would think that it is shaft lubricant cooling water and that if it shouldn't be there the shaft would have siezed up along a time ago.
The area in question is (looking at the pic from the right) just above the water intake where the surfaces meet and they begin a long swooping "S" curve.

Again - Thanks in advance for your advice / opinions .