I know of some Roborovski that have markings that are dark enough to appear black and the father of Simeon, my old Blue Pied boy had very dark markings so I suppose it's possible that your Robo could be Black/Blue.
Here's a photo of Simeon's brother Reuben showing the colour on the markings... I know this one is patchy as he's a pied but is your hamster a similar shade to Reuben's darker patches?
Reuben by
Metallica Hamstery, on Flickr
Do you have a photo and then we'll be able to have a better idea on whether she is a Robo?