Regarding doubt, he should aim for what is most likely correct. A man said to him, "From the Prophet ﷺ?" He replied, "As far as I know."
حدثنا حجاج أخبرنا شعبة ومحمد بن جعفر حدثنا شعبة عن عمرو بن دينار عن سليمان اليشكري
في الوهم يتوخى فقال له رجل عن النبي ﷺ قال فيما أعلم
Its isnad is sahih, from both of his routes, and Sulayman al-Yashkuri is Ibn Qays, and the hadith has previously appeared at 11288.