To answer your question about the sand skirt attachment points, yes those should be holes for bolting them on. Unless, of course, the Brits and Canadians actually filled them back up with the bolts after removal. That part I'm not sure about. Maybe someone else out there knows for sure.
I have always attempted to drill them out. This last time I used a number 79 drill (.0145).
Don't know why Dragon would make the holes as raised bumps (rivets/bolts)!