Knowing FAS's penchant for modeling high end/boutique gear, one could do some googling around the interwebs and make some educated guesses as to what each preamp is modeled after. For example, the Transformer version might be based on the Neve 1073 series, or perhaps one of the famous API's. The various tape versions might be based on some legendary 2" tape machines from the days of Yor - Studer A827, or maybe one of the Sony decks. The FET based versions may be recreations of famous recording desk input channels - Harrison, SSL, Trident, etc. Or it may be none of these. Ultimately, it's irrelevant. The great sounding gear of the past (and present) wasn't considered 'great' because someone knew the name of the beast. It's considered great because of how it sounds, and the character it imparts to the signal going through it. The only sense we determine that with is our ears.
Yeah I get it, the Axe's are modelers and the amps/cabs have names. Yippee. Don't get hung up on the name. We have the most innovative, comprehensive and most ridiculously fun guitar tool on the planet at our fingertips. Create, tweak, play and smile.