If you are buying severums from an LFS and they are tank-bred, it doesn't matter what they're labeled in most instances -- they are going to be mutt fish. They will be considered greens but probably have been spawned at some point with turquoise, golds, or any of the regional variants available. The best way to get a fish with the color you want is to pick out an adult fish that catches your eye. There's no way to know as juveniles how they'll turn out.
The fish in the original link is what I'd consider a typical H. efasciatus green. "Green" tends to refer to the base color of the fish which is usually an olive or hunter green color. The striations and facial markings will still be iridescent blue.
There are a lot of factors that determine a severum's color -- water quality, tankmates (whether it's a dominant fish, whether it feels threatened, etc.), food, the presence of a mate, etc. They darken and lighten, show bars or hide bars, etc. based on all those factors. What it looks like today may not be what it looks like tomorrow. That's why it's hard to point to an individual picture and say, "I want that exact thing."
The Rio Maica severums that Jeff Rapps had will probably turn out pretty blue if you can get ahold of those. From a small size they were already showing a nice base color and decent iridescence.