Is the Hadith of Ibn Mas'ud, which states: "I counted the Prophet's - peace and blessings be upon him - movement of his forefinger and found it to be 49 or 59 movements," authentic or not?

Muslim narrated from Ibn Umar that when the Prophet, peace and blessings be upon him, sat in the tashahhud, he would place his left hand on his left knee, and his right hand on his right knee, and he would form a fifty-three shape and point with his index finger. Al-Nawawi explained that "forming a fifty-three shape" does not mean counting, but rather placing the little finger on the palm, which accountants call fifty-nine. Al-Shawkani mentioned various ways of placing the right hand in the tashahhud, including clenching all fingers and pointing with the index finger, and placing the hand without clenching and pointing with the index finger. The meaning of "forming a fifty-three shape" is a known method among Arabs for calculating numbers. Placing the right palm in this manner is one of the sunan of prayer, and it is not true that the Prophet would move or point with his index finger fifty-nine, fifty-three, or twenty-three times.