The term "contrast sight" is SiG's standard offering. To clarify when you use them, you "dot the i". The front sight is a dot, and the rear sight is a notch type sight with a single solid vertical line centered. You "dot the i" by superimposing the "dot" where you want the impact to be (not like a six o'clock low style hold). Then you line up the front and rear sights by making it appear like a lower case "i"......*bang*.
If it doesn't say "3 dot sight", it will not have them. SiG currently uses Meprolights as it's night sight vendor and they are a 3 dot configuration with tritium vials that illuminate in low light/dark conditions.