New in Mountain Lion, Cocoa apps include support for the NSUserNotificationAlertStyle key in Info.plist, which allows the developer to specify a default style for their notifications.
Obviously, the user can change this, but it makes sense to allow the developer to provide a sensible default.
Does any parallels to that exist in iOS?
Only the user can change the default alert style, which is found in the Settings > Notifications > [APP]