I've only had my TCS 3years. Just about all my knowledge if these is from the internet, mostly this site.
The SJS one is more like mine (a mount on each "trumpet"). The Ebay one is probably more specific to Elan as in the description - the trumpets look shorter too, and it seems to have more holes in the side. There should also be a plate that fastens to the side and attaches to the side of the luggage box. There is a drawing at the end of the Fuel system section of the Twin Cam service manual.