The tread should be fully vulcanized to the point where there isn't a forward/back distinction.

The casing does have a seam in it, but with overlapping layers that would reduce the significance of that seam.

Tread/casing separation does occur, but I'm not convinced there is a directional component.

I don't remember any discussion about casing separation at seams. Blowouts and tube herniation do occur, so perhaps that would give more information. Still, it doesn't seem like the seams are a major directional component.

There are many road tires that don't have those directional arrows.