I believe you have Mary Polly Parker attached to the wrong John Simmons. I have her married to John Simmons Born October 10, 1759 in Franklin Co., N.C., and died April 5, 1923 in Montgomery Co., Tennessee.
I have Pension papers for John & Mary Polly Parker in 1818 and again after John died, and Mary applied for a widows pension and drew it until she died in 1940/41.
It states in the pension (1818), that John & Polly had a 13 year old son still living with them, Bsrtlet, so he would have been born about 1905.
I have this John's father as John Wiley Simmons born about 1731 Granville Co., N.C. (according to a Will), not 1745 as many people have his birth date, and death 1790 in Franklin Co., N.C. Also, I have this John 1731 married to Mary "Molly", born in 1745 and died on Feb. 2, 1802.
Don Kelderman