Rear Main Seal?

[armybyrd]

My '83 stepside's 305 has an oil leak that drips down the starter-it happens for a few seconds right after I shut the engine off. I just changed the valve cover gaskets and I didnt feel anything by the intake manifold. Theres also sludge and oil around the heat shields around the exhaust manifolds though I checked and the valve cover gaskets arent leaking. Does this sound like a rear main seal leak? Again it drips down for a few secs after the engine is shut off.