Re: What guitar(s) are synonymic with these decades?
Much as I love SG's I can't really see them as being a dominant guitar in the 60's - I would say that was more LP's and Strats. Who were the 60's SG guys ? I can think of Pete Townshend, Eric Clapton, Santana, Tony Iommi, Robby Krieger, Keef and Mick Taylor in The Stones. Actually that's a fair few - any others ? Although the only one that's stayed with the SG is Tony Iommi. Oh, and Robbie .
I don't know how many people got turned on to the LP by Eric but there can't have been too many to go around considering that they weren't being made and most of them were in the States.
Clapton used his LP Std & Custom for a few crucial years (Bluesbreakers thru Disreali Gears), and his choice of guitar & amp influenced
many Brits in the mid and late '60's, whose music was huge in the USA. It's a who's who of 1960's British blues-rock: Jimmy Page, Jeff Beck, Peter Green, Danny Kirwan, Kim Simmonds, Mick Abrahams, Robin Trower, Martin Barre, Luther Grosvenor, Keith Richards, etc.
Some Americans also followed suit and got LP's, like Mike Bloomfield, Joe Walsh, Duane Allman, etc. Even though it was out of production for part of the decade, the LP was the weapon of choice for many of the best guitarists in the 1960's. High profile on both sides of the Atlantic.
SG's may have been more popular in the USA, especially with west coast bands, but some of the big name Brits used them too, like Clapton, Simmonds, Trower, and Mick Taylor. The SG was a strong contender throughout the 1960's, but lost some popularity when Gibson redesigned it in 1970.
Look at film clips of the rock bands that made up the first wave of the first 'Britsh Invasion' in the early & mid 1960's, and most had a 335 or two. Later in the decade, solid bodies had taken over, but even then Clapton & Alvin Lee were using 335's.
Except for Hendrix, I don't see Strats nearly as prominent in big name bands as Gibsons in the '60's. I think the Hendrix effect really kicked in during the 1970's (he was Fender's greatest marketing tool), which led to Super Strats in the 1980's.
Doesn't matter who stayed with a certain guitar model, if they played it thru a decade, that's identified with that decade's history. The classic image of Carlos Santana at Woodstock is with an SG Special, not a PRS. Hendrix 'cheated' on his Strats, and also played SG's and V's, live & in the studio.