The Caprica viper is not the mk1, some people are just calling it wrong. We've already seen the mark 1 in the mini-series and it's been established it looked pretty much like the original show one. The one in Caprica was some older atmospheric fighter that looked to be on a similar tech level to our current fighter jets. Since it was seen in the virtual world it's possible they were playing some "historical" sim or even using a made up fighter (colonial version of crimson skies?) Sure it was called a "viper" but that seems to have become a colonial term for any fighter.
At any rate, I doubt she'll appear in our game any time soon because we have other priorities. People are welcome to mod it in, though.