A commonly found birthdate for James Sr. is 16 Oct 1703, which is quoted in many trees and references. Given his death date of 1777, and the supposed ages of his children, this seems to be a reasonable timeframe to assume for his birth. There was a James Wilson born to James and Mary Wilson on 16 Oct 1703 in North Farnham Parish, Virginia. However, after reviewing and analyzing many wills from Richmond County, I am convinced he died in 1746 leaving no heirs. There was another clan of Wilsons with several James in that County also, but the last of them seems to have died in 1744, and his father married in 1712 so he would not be the right age, nor are any of the other James in that group. This other clan lived in Lunenberg Parish, which was formed from North Farnham Parish in 1732. The only will I can find in North Farnham Parish for a James Wilson was in 1745/6 — it mentions his cousins Moses, John, Sarah Ann and Mary Wilson (who could be his nieces and nephews in the terminology of the time), and his brother John. A son John was also born to the same James and Mary Wilson in 1710. Thus, I conclude that the 16 Oct 1703 birthdate which is widely quoted in most trees and references most likely incorrect for our James and belongs to this other James Wilson.
Many trees also show James as being born in Augusta, Virginia (as well as his supposed father, Robert). These claims range from highly improbable to impossible, as Augusta County was not even formed until 1738, and the first known settlers arrived only in the 1720’s. There was a James Wilson (and likely brothers) that acquired land in Augusta County in 1754 (in Beverly Manor), but he died there in 1768 (see https://www.werelate.org/wiki/Person:James_Wilson_%28200%29#Records_of_James_Wilson_in_Augusta_County.2C_VA for details) so this is not our James.
I did find another birth record for a James Wilson born in Kent County, MD in 1726 (whom I believe married Martha Cowarding, but that is in another post), but he would be too young to be our James.
If there are any other possible birth records that others are aware of, I would be glad to research them further.