Yes! If the application feed is accessible to "anonymous" users (i.e. non-members), it is available at the following URI:
<PUBLISHED_MASHUP_NAME>.googlemashups.com/feeds/app/<STRIPE_NAME>
Likewise, if the user feed has been set to read-only, it can be accessed at:
<PUBLISHED_MASHUP_NAME>.googlemashups.com/feeds/public/user/<USER_EMAIL>/<STRIPE_NAME>
This returns the specified user's feed. Please note that <USER_EMAIL> is case-sensitive. To enable your mashup's users to easily locate a custom feed, you can place a gm:subscribe tag in your mashup. This creates a link to the feed, which can then be subscribed to by an RSS reader.