You're right about the Firebrand "losing it's way"... I recently had spotted one from the early 80's on my local Craigslist... Besides being red, and having "The SG Firebrand" on the truss rod cover, I was scratching my head as to what "Firebrand" was meant for (thinking maybe because of the red, something to do with Firemen... lol)... Then upon digging discovered that they were originally actually "firebranded" and had that natural wood look to them including the headstock. At that point the "Firebrand" made sense - not so with the later regular looking models. Must be like you say - Gibson just wanted to use up the parts and slapped them some regular SG Specials or Standards. Shame. But models like that come and go unfortunately...
cheers