Good answers all!
I have found out that the XPS 8300 I7 2600 system that the Radeon 6700 is an option in (among other Dell systems I assume) has an optional bracket that is supposed to secure the end of the video card in the front of the case. The bracket is depicted in the 8300 Service Manual (as an option)
There was no bracket listed in the detail parts list in the Order Confirmation from Dell for the 8300 I ordered (refurb from Dell Outlet).
So I guess that Dell decided to do away with the optional bracket but still installs its OEM Radeon 6770 cards that have the extension (?).
It is somewhat odd looking in that the extension, while securely mounted to the video cards PCB, simply hangs suspended in the case touching nothing and doing nothing.