False Percula vs True Percula?

Hello everyone!

I bought two 1" long tank-bred Percula Clownfish at my LFS yesterday and
they're doing well. A friend of mine came over today, looked at the
fish, and said that I had been sold False Percula Clownfish, not true
Perculas. When I asked him what the difference was (IE how he visually
told the difference between the two) he said he couldn't describe it -
just that they wern't true Perculas.

Well, I'm personally happy with the fish. They look good, eat well, and
have alot of energy and "character". Plus, since they're the first fish
inhabitants of my 65g tank they're also the only swimming thing to look
at (the crabs and snails were nice for the first few days, then they got
old).

So, my question is this - how can I tell the difference betwen a true
Percula Clownfish and the False Percula Clownfish (also called the
Ocellaris Clownfish, False Clown Anemonefish, and Anemone Demoiselle)?

And does it matter which I have?

Thanks,

mark h