just went out and tried the cap from the Team Issue crank on the Gossamer crank.
It covers the opening fine, but internally its too lose to stay in place. A little putty, glue, gum, or a thicker O ring and it would work fine.
Cosmetically, it fits flush, and hecks its got a CF weave finish!
__________________
You could fall off a cliff and die.
You could get lost and die.
You could hit a tree and die.
OR YOU COULD STAY HOME AND FALL OFF THE COUCH AND DIE.