No its not, at least in LA. You must have knowledge (Reasonable knowledge) that it was stolen to be charged with receiving stolen property. Once you learn that it was stolen, and reported, it is your responsibility to turn it in. If not, than you can be charged with stolen property..
Retired police by the way (LAPD).....
http://legal-dictionary.thefreedictionary.com/Receiving+Stolen+Property
Elements
"Receiving stolen property is defined by statute in most states. Generally it consists of four elements: (1) the property must be received; (2) it must have been previously stolen; (3) the person receiving the property must know it was stolen; and (4) the receiver must intend to deprive the owner of his or her property."