Override add-on block template (ie: tweetcrete) in my new theme2 users found helpful
it depends on what you want to do. But if you're planning to change the output template just copy it from:
Any changes you make in the latter one will be used to dispay the block.
Someone else can chime in on this but I don't think a view.php simply in a package override would work.
If you want to do this site-wide, i would look at in your theme's areas:
function setCustomTemplate($btHandle, $temp);
you might have to play around with the second arg with .php or not being included in the file.