Genesis tanks used to be made by Pressed Steel. In fact, IIRC, they (Sherwood then) were the
first to market Pressed Steel HP tanks around 1990.
Not all of them. I have a HP120 Genesis tank in my garage that has the 5250 SPUN designation on it and an Asahi hydro stamp. I know of a bunch of HP100 Genesis tanks that were Asahi's also. The key is looking for the SPUN stamped in the crown. AFAIK, nobody else uses the spun construction method.