From 1958 through 1961, Hamilton produced the Chapman, featuring the 770 movement. It was part of the "Medallion" line up. Hamilton also had a "Masterpiece" line of solid gold watches and a "Medalist"series of gold filled watches. I imagine the Medallion series was a step up from the Medalist series. It's hard to say though, as Medalist watches were still a premium level versus Hamilton's other less expensive rolled gold plated models.
Here's a Chapman that I received as a wreck and was able to restore to it's former glory.
As received, it had lost it's crystal and had developed a serious case of "dial rash". In addition, the hands were very corroded and needed to be replaced (although they can be refinished too).
With the case nicely polished, a new set of hands, a nice glass crystal installed and professionally refinished dial - this Chapman was a thing of beauty.