Hi Chris,
This patch is already committed, but, I'm afraid, it's wrong. Setting these registries has nothing to do with installing Gecko. Setting them in Gecko installer will only make supporting it harder. We don't want to tell user to "run iexplore about:blank" to get an app working.
I will send a better patch that always sets them. Last time Alexandre didn't accept such a patch, because of apps that need native IE and install it only when this key is not found. It looks like it's time for such change.
Thanks, Jacek