I was talking to Ben Siegel this weekend, and he said that it's very hard for some people to tell the difference, and unfortunately - a lot of animals sold as specters are not proving out because of that. He used the Specter as an example during our discussion at the Repticon show.
We were actually discussing his het Sentinels and what was it that someone saw about them to go "I think I'll pair them up and see what I get", because let me tell you - there's nothing distinctive about them to me - and Ben even said - he wouldn't want to sell one as a het unless it came from a visible.
That's how we moved to discussing specter/whirlwinds and how difficult they are to tell as well.
If you put that light baby in with a bunch of other light babies - I don't see anything in particular that would distinguish it from them, unless there's something subtle that we're not seeing in the picture.