I certainly would not speak for the sellers, but these wheels sure look cast to me. Look at a picture closely, and you will see the max weight imprinted in the casting. Also, the design of these lend themselves to a casting, not a forging.
There is precious little information on the US seller's website, and little more on the Australia website.
http://www.performancewheels.com.au/industrial.asp#
Another thought: The max load for this wheel far exceeds the max load for a similar size Alcoa true forged wheel. Alcoa forged has the US reputation for about the toughest wheel out there. I wonder if Alcoa is quoting a number that passes a US standard that Performance Wheel (Aus) does not have to match. Anyone know?