I'd pass.
They may be dyed, in which case the coloring will be gone within 2 molts.
AFAIK, There are blue shrimp that aren't dyed, but they tend not to maintain the color unless your water's perfect. The color may or may not be passed along to their progeny. It's pretty dicey all around. Snowball, Diamond, Crystal, Cherry, Bee, Yellow, Green & Tiger shrimp colorations all breed pretty true and vary somewhat w/ water conditions - but they'll never fade like blues do.