A colleague here recycled his copy to me, and like the guitar geek that I am, I spotted a misleading error in the third sentence when they called S-100 "Guild's mid-'60s answer to Gibson's SG."
Yes, the S-100 came out in 1963, but it didn't resemble an SG until they reintroduced it in 1970. So technically it would be a mid-'70s answer to the SG.
From a 1963 Guild catalog:
From the 1970 Guild catalog:
Despite that, the article is definitely worth reading.