I'm pretty sure the original "Six Flags" were the ones that flew over Texas, which is why they had a Six Flags in Texas to start with...American, Mexican, Confederate, Texan (republic), Texan (state flag)...which else that I can't think of?
I believe that after they built the first three, they then went and bought a park outside L.A. called Magic Mountain, and just added the Six Flags. Then, when Mariott sold their 2 Great America Parks, KECO, or whomever was in control at the time, bought the one in Cali, and Six Flags bought and branded the one in Chi-town.
Six Flags then purchased Astroworld from that Judge Roy guy, and branded it, and they then bought and branded Great Adventure in Joisey.
I believe that Fiesta Texas was put under SF management and re-branded Six Flags Fiesta Texas before Premier became SFI. I'm also not sure of Darien Lake. I don't remember what year Premier became SFI.
As for that, I think all the other American Six Flags Parks were Flagged after Premier took over. I could be wrong about Kentucky Kingdom. anything after 1999, though, that was branded, was either owned by Premier prior, or was bought by SFI after the change.
Sorry to double post, but there were 3 'original' Six Flags Parks, then 4 that were bought up by the original company in the 70's. After that, I'm not fully sure, but I'm sure someone here can elaborate.
Six Flags Over Texas, Six Flags Over Georgia and Six Flags St. Louis (Over Mid-America) each have their own "six flags" for their own history. Each park takes their "six flags" from the different people that have controlled the area the park is located in.
Six Flags Over Texas - France, Spain, USA, Mexico, Texas and Confederate. Six Flags Over Georgia - England, Confederate, USA, Spain, France and Georgia. Six Flags St. Louis (Over Mid-America) - Missouri, Spain, England, Illinois, France and USA.
Don't worry CoasterQueen, you're not the only one. We appear to have two different conversations going on here. I've never been to Magic Mountain, but I first became familiar with it back in the very early 80's. The movie KISS meets the phantom of the park was filmed at the park and had plenty of apparent stock footage of REVOLUTION, as well as, The woodie I'm assuming is COLLOSSUS today. But the branding by SF must've come after that because there is never any mention of SF over the loudspeakers in the movie, (and it seems as though every other seen has the audio of the loudspeaker guy announcing the KISS concert at Magic Mtn.! If you've ever seen the movie you know what I'm talking about.)
Also, the credits give thanks to Magic Mountain, but no mention of Six Flags at the time.