The front glossy area looks like it should be a turret (with the guns on either side). What if the original version (storywise) was in fact a bomber (not a big one, but something more similar to the naval dive bombers of WW2). If that small thing carried a very large bomb, it's manouvrability could go low enough to need a turret. In more modern times, the Vasudan have larger bombers with internal bomb bays, and so the Anubis, which is very cheap (and reasonably manouvrable without the bomb), has become a fighter with fixed guns and a more advanced sensor suite in the turret housing.