That doesn't look like a Sailfin Molly, just a standard Molly, Dalmation in color. She does not look pregnant to me. See the image below for a Sailfin picture.
Maybe it's just the picture, but the female doesn't look Sailfin type to me. Either way, great fish, but I don't think she is pregnant. She will be shortly though if all things are normal.
well the dude at the lfs store said all of the fish in the tank were sailfins and shes the same size as my male too but the ppl at the lfs's never know anythin about fish.