I've never heard this... which, of course, means absolutely nothing. In our Ryu sai are "roughly" attributed to non specific Chinese or Indian weapons, or possibly to an antique Okinawan police source. It's purely conjectural.
I did try to find Gen on that website but could not, just to compare shapes. The video was not clear enough for me, but they looked ot be the same as sai. Looks like they have the video, but not the weapons for sale.