Gore Windstopper’s Infinium is just a variation of Gore Windstopper. Just like Gore Windstopper Active, which is used on models like the j61-ws, j73-ws, and j47A-ws. Goretex infinium is a variation of Goretex (previously PB). Not sure if there is any difference between PB and Goretex Infinium. Windstopper infinium seems to be very similar to the material used on the J46U which is lightweight and my guess would have a much more abrasion resistant face fabric compared to Goretex Infinium/PB. GT Infinium/PB is lined with fleece and although lightweight, probably not as lightweight as WS Infinium or WS active.
edit: realized the material for the 68-ws states Gore TEX Infinium Windstopper which is confusing since I thought they separated Gore Windstopper, and GoreTEX.