Looks suspiciously like marine/ reverse rotation to me, what say you?

My HD parts book says the P/N is for a 413 Industrial Truck w/2bbl intake.
1964-65 COE Trucks. R308, T308, T310.
I suspect it's for an old cab-over tractor. If I recall, those 2bbl intakes were worth some $ at one time. He probably dosesn't have that anymore.