box 7 1099 r

My 2020 1099 r has a gross amount of $4,600 in box 1, $4,300 in box 2a, taxable amount and $300 in box 5 representing my contributions. In box 7 there is a "P" which is for 2019 contributions that are taxable in 2019? This 1099 r represents payments from a defined benefit plan where I was employed in the 1980s. So, there were no contributions in 2019. I have read that I can simply change the code in box 7 from a "P" to an 8. Is that correct?