probably cus of better sense of imagination ;]
i've seen lots of mass-production rear dropouts - typical gipiemme/shimano/suntour/campy are just unable to be mod'ed - to big triangle "window";
this one (i'm asking bout) are:
1.deaper than the rear stays tubes
2.very long (longer than typical ones)
3.and that space for rear wheel's axel regulation seems to be placed properly - in the middle (if the drops were modified - they would be probably un-symethric, oddly moved to the front...)
this ones are for sure original ones.