That doesn't always seem to be the case however. Just like leos being called BD, nearly every motoro for sale these days is labeled as a marble, pups and adults alike. I've also seen pups born with tons of marbling from stunning parents to grow into boring adults, I've also seen it go the other way too. So just because a pup comes from two marble parents I would have a hard time calling the pups marbles until they get a bit older.
Also there do seem to be at least a couple types of marbles. I believe I know the kind you are speaking of, they tend to have the "bars" between spots? Much more structured patterns? There are also marbles that have swirls and blotches between spots. These don't have nearly the same look and tend to sell for a bit less, though I had always heard of them referred to as marbles as well. Maybe these are no longer supposed to be considered marbles? Like I said, been out of the game a while, just trying to understand at this point.