I paid close to that same money for a used Diamondback, about one year ago.
The finish wasn't nearly as nice as the OP's gun, matter of fact, the one I bought appeared to have been refinished by a police armourer, because it was a utilitarian polish/finish.
The gun was nice and tight, and appeared to have been fired sparingly.
Rather than polish/reblue the gun, I had it Nickel Plated, and it was returned to Me just before Christmas.
Well worth the cost for the finish, and the 6.5 month's wait time!
Here's one of the images: