This SG belongs to the loved/hated Norlin era.
This means it was built between 1970 and sometime around 1986, loads of guitar enthusiasts hate this era and they will swear that they are the worst guitars Gibson has ever built, but to be honest most of them probably have not tried a Norlin era Gibson, and this feeds the inflated price of the pre-norlin era gibsons, this is why a 1968 SG will set you back around £8k and a 1971 will cost around £1,5k.
This is a great guitar, it’s incredible how fast the neck is and how effortless you can go through the fretboard, this is the reason why they earned the nickname of “fretless wonder” this happens because the action is really low and the frets are not very tall.
Playing these “fretless wonders” does require some time to get used to, it does challenge your ability to perform bends and you have to get rid of the “heavy hand” habit (if you do have it) but once you get used to them, they are great.
Of course this guitar is also part of Angus’ arsenal, (and this the reason why I bought it) you can see him using it on the “Flick of the Switch” video (https://www.youtube.com/watch?v=DWKcJwuZnzE) and he also used it live on some occasions.
On this model Gibson implemented 2 curious changes: the inlays changed to a rectangular shape and the output jack changed from the top of the guitar to the side. Personally I love these inlays, they do look great and you get an extra one! (the 1st fret gets an inlay as well, where as before only custom guitars would bring an inlay on this fret). It also has the “speed knobs” not sure how “speedy” they are, but they move smoother than the black top hats.