Guns, guns and more scary guns
Firstly, you can't tell by looking because Airsoft guns are replicas all the way down to the manufacturers stamp. It's one reason that they are sometimes used in movies. They look exactly like the real thing. (Other than the law mandatory orange on the muzzle, which can be removed like sofa cushion tags.)
Which comes back to the picture. If real machine guns are illegal to have where that picture was taken *probably* those are toys. But I don't see orange on the muzzles, but that doesn't prove anything either.
Oh what the heck, see what the commentators (I really hate that my spell checker thinks "commentors" is wrong) at Say Uncle have to say about it. (Perhaps it's just me, but wouldn't the "real thing" at a gun expo have a cable on it? Or do they really let people pick up the expensive stuff without supervision? I'd think that the sellers would lose their stock.)
I have an MC51 like this one. (Changing the battery is a bear for this model unless they fixed that since I got mine.)