Another butchered Gibson fretless...
Was an SG once...
That's not a '68. It's a '70 or '71 EB-0L -- you can tell it's long scale by the position of the bridge.
It's not butchered. It's missing the pickup ring that all the slotheads had. The one missing fret is repairable. The rest of the defret looks good.
That action is high enough to do some limbo dancing underneath!
Or as I used to say, you could slide Calista Flockhart in there.
If the action is as bad as it looks, I'd pass unless the seller is willing to take it to a tech. If it can be adjusted to normal, $700 or offer is reasonable.