roger, roger ...
the original goal was for one vent to face forward to channel fresh air into the engine compartment ... and the duct was wire tied so that it fed low into the compartment.
the other vent was facing aft with the duct wire tied to something high to vent the hot air out of the engine compartment.
I am thinking that perhaps the aft vent doesn't really need a duct in the original model. The engine cover is a lot smaller in the 500 series.
But the idea was to get forced cool air in, and then vent the hot air aft.