Was the Sunkist already berried when you got it? If that was the case, then the offspring would still be sunkist shrimp (ie. if you were successful raising the Sunkist offspring). Sunkist larvae apparently need brackish water conditions.
Note: Sunkist are generally of the Caridina genus (Caridina cf. Propinqua). There is a Neocaridina genus called Orange Sakura.
So assuming the LFS has labelled the shrimp correctly then there is a lower chance of interbreeding. But people make a very common mistake of using the Sunkist and Orange Sakura name interchangeably and messing things up.
But if that "Sunkist" shrimp somehow mated with the Red Cherry shrimp, then you would get diluted genetics, and some offspring would carry genetics of both Sunkist and Cherry. That means the offspring will be of poor quality eventually leading back to the wild type look.
Maybe a picture or two of what you have would help. Close up side shot of the shrimp please.
I'm going to borrow a pic from the interwebs (credits to whoever the original photographer is).
The Sunkist (caridina) has a slight hump in it's back with distinctive white or red stripes. The hump is similar to Ghost shrimps. Notice the colour is a lot more transparent.
The Orange Sakura is more uniform in colour. Good quality varieties are less transparent than the Caridina Sunkist.
Of the two, the Sunkist is the rarer find.
Hope that helps.