Abu al-Rabi' (may Allah have mercy on him) narrates this same hadith from Hammad (may Allah have mercy on him) with the same chain, except that he said "sadaqat al-fitr" without expressing any doubt, and he said: "of dates, one year." He also added: Abdullah used to give it when those who received it sat (to collect it), and they used to sit a day or two before the Fitr.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الزكاة / 7679