The utility should be able to be used to find HWGrowl installs, they
will get listed on the second tab of Growl Version Detective.
Unfortunately, app store issues such as its over zealous detection are
out of our immediate hands. We have filed bug reports with Apple on
the topic, but obviously they haven't been resolved yet. As for
testing different versions, I wind up deleting and readding things a
lot. Also, Im rarely off the development version for too terribly
long, only when I need to go back and confirm behavior in a previously
shipped version.