Re: John Lackey SR d 1783 Amherst VA

Hi John, While I'm not related to Samuel Lackey as far as I know, I am curious to know more about him. He witnesses on the marriage bond for Rachel DAWSON and Alexander Barnett in 1786, along with a Margaret Dawson, which is not Rachel's mothers name on any deed at this point.
I have Rachel's father, Henry Dawson, in Augusta Co., VA in 1770 buying land in Beverley's Manor and being in Amherst Co., by 1780 petitioning the court for his military land grant earned by his service in the French-Indian War from 1760-1763. Henry only has his wife, children, grandchildren, etc. in the area.
I'm trying to figure out where Henry Dawson came from prior to Augusta and am hoping that one of his neighbors or one of the witnesses on his deeds or children's marriage bonds will give me a clue.
Rachel and her husband Alexander Barnett also moved to Madison Co., KY, sometime after the 1801 Amherst Co. personal prop. tax record was taken.
I appreciate your time and help!