1986 VF500F Strange gasket on left crankcase cover

Can anyone explain to me the purpose of the small gasket under the left side crankcase cover on the VF500F engine? It is part # 11343-KE7-306, reference item 3 on fiche page "LEFT CRANKCASE COVER @ WATER PUMP." This in on the backside of the cover that the slave clutch cylinder gets removed from. It doesn't appear to seal anything.

The reason I ask is because I had this cover powercoated (after leaking brake fluid destroyed it), and the gasket was destroyed during removal. Of course the part is no longer available, so I suppose I can make one out of gasket material if necessary.

Thanks!

Dan