I’ve been thinking about the manufacture of aes signatum. The bars clearly have an up and down along one short end. ‘Up’ being my shorthand for the fill edge, where the bar has been broken from the casting sprue.
This got me to observe this about known RRC 12/1 specimens (all illustrated with fill edge up).
specimen in trade (ex Goodman collection)
I cannot readily determine the orientation of the specimen illustrated in Vecchi 1978, but up dolphin seems most likely from the photos.
Concerning but not decisive. If you look back at previous Vecchi images of amphora/spearhead. You’ll notice that on have amphora up and the other amphora down.