I've been leakin oil from what looks like the breather. but my question is, is there a gasket behind the crankcase cover?

 

what do you mean "crankcase cover"?

 

where the crankcase breather screws in

 

i dont remember but those fumes will take the path of least resistence, there isnt much pressure to evac. those fumes, for it to leak out from its mounting point, u must have a blockage in the vent line, make sure the puke bottle is either removed and or empty. if it is still there do yerself a favor and remove it and extend the line further. if your line is bloked clear asap it can blow out your rear main seal.