Musannaf Ibn Abi Shayba 13:2301

Abu Bakr narrated to us, he said: Ghundar narrated to us, from Shu'bah, from al-Hakam, from Ibrahim, that he used to dislike that a man sells a dinar and takes some of it in gold and some of it in silver. He said: And al-Hakam used to see no harm in that.