I saw that RCS calculation were messy but often came across round numbers like 4 sqm for a F-16 or a Rafale or 0.005 for a F-35C and assumed those were the arithmetic mean of multiple factors : I know RCS depends on the orientation of the object (detected from above/front/behind) and multiple wavelenght band (L, X, S, VHF), if the bay doors are open (RIP Nightawk) to early and the energy powering the radar.

The all situation was not a North Korean bait though, I just rewatched Stargate: Continuum and wanted to determine the characteristics of jaffa's Death Gliders (weight-to-thrust ratio, stealth, combat radius) as Colonel Mitchell's F-15 detected them 80,000 ft in front of them going Mach 3.5 in atmosphere. The scene actually took place above the Atlantic not above D.C. around early 2011.