That may be true, but was the property stolen?
Did the one finding the phone take steps to return it to the owner? That is the real question. And even if the phone is deemed stolen, now they're issuing a search warrant for what?
If those phone was not stolen, the referenced laws apply.
In this case, Gawker wins. No doubt.
Here are my sources.
1.
2.
But the police don't need to know who sold it to Gawker in order to pursue action against Gawker. They posted the entire details of their "crime" on their website, and the police were just taking physical evidence in order to back up their case for trafficking in stolen goods. This in no way has anything to do with the cited laws.
In fact, the only way they could refute what they've already published is by revealing their source, if the source had a different story to tell. And if they try to claim that they made up the story, then they probably lose their journalistic protection if they were lying in official "publication."
Gawker has had something like this coming to them for a long time.