I just bought a 1974 High Standard Flite King based Riot model in 12G from a Gunsiter. It will go nicely with the '56 Supermatic Citation I already have.
It appears to have seen very little use and based on the photos I got looks close to mint. They were well known for the smoothness of their action and their durability and were used by a lot of police agencies in the US into the '80s.
It's an odd one as despite being marked as a Riot model and having an 18.5 inch barrel it has a number of features of the Deluxe field model including sling swivels, a ventilated butt pad with spacer and an adjustable poly choke. I haven't been able to trace reference to one of the same configuration so it will be interesting to look into it a bit more.
It's in Cape Town and i'm only planning on being there again in Feb so I have a bit of a wait ahead of me before i can fondle it up.
For the ballies amongst us the Riot model was used by Steve McQueen in The Getaway where while shooting up a Sheriffs Deputy patrol car he displayed some of the most realistic shotgun management I've ever seen on the screen and probably has a bit to do with me developing a love of shotties.