Actually thats not where it directly becomes theft, but where it becomes rather more unclear. As was reported, the guy tried numerous times to return it to apple, and the reports say that he was told by Apple what he has is just a knock-off, and not to bother them about it. Granted, he was probably only talking to monkeys on apple's helpdesk and only got a TR for his trouble, but if theyre the only point of contact apple will provide to him, then by the law you just quoted he clearly did make "reasonable and just efforts to find the owner and restore the property" by contacting them, whereupon the owner told him the device wasnt theirs and they didnt want it. Both the guy and Gizmodo clearly had strong evidence the device was Apple's, so no effort was reasonably needed to locate any other potential owner, and he made all reasonable effort to return it to Apple before selling it (as reported, anyway).
If the owner is unknown or has not claimed the property, the person saving or finding the property shall, if the property is of the value of one hundred dollars ($100) or more, within a reasonable time turn the property over to the police department of the city or city and county, if found therein, or to the sheriff's department of the county if found outside of city limits, and shall make an affidavit, stating when and where he or she found or saved the property, particularly describing it