Evidence of a statement previously made by a witness is not made inadmissible by the hearsay rule if the statement would have been admissible if made by him while testifying and: (a) The statement is an identification of a party or another as a person who participated in a crime or other occurrence; (b) The statement was made at a time when the crime or other occurrence was fresh in the witness' memory; and (c) The evidence of the statement is offered after the witness testifies that he made the identification and that it was a true reflection of his opinion at that time.