There are some very well known scamming techniques and just scammers, period.

One scam method is put a pearlized glaze or shalac over top of the first set of baby ponies in order to try to pass them off as "pearlized". Pearlized babies of Glory, Moondancer, Surprise, Cotton Candy, Blossom, and Firefly were introduced as mail orders in the last years of My Little Pony. They looked very similar to the original set of babies but there are some differences to look out for.

An authentic pealized pony will not have a glittery symbol. Period. It will be a normal painted on symbol like Applejack or any other normal pony. Plus, the original baby pony unicorns Glory and Moondancer had a different strip of color in their manes, while an authentic pealized baby will only have a solid colored mane. In addition, Mail order Baby Moondancer has a purle moon and pink stars for her symbol colors while the original Baby Moondancer's symbols are all one solid color. Lastly, Baby Suprise has a more definite yellow twinge than her store bought counterpart.

One of the most infamous indentifiers of a pearly baby is that the pealy glaze went right overtop of their eyes giving them this weird dead fish stare. Many times scammers don't realize the shalac goes over the eyes and just leave them normal. That's a big indicator that the baby is not authentic.