I am replying to you because curiosity has gotten the best of me. I remember tracking a Ben Bogart or Bogard in Texas thru the 1850 census, while his parents Pryor and Perry Bogart still lived in Grayson County. Pryor Wallace married Captain John Hart. She was the mother of my great grandmother Roxcina Hart Watson Hardin.
John Hart had children by another wife. Those first group of children made it very hard on Pryor that she had not a marriage doccument to prove her marriage to John Hart Pryor was left with young children to raise and she married Perry Bogart who lived in the county in Texas. Their son was named Ben. He was about 15 years old in 1865. I followed him through the census years until he was 70 years old. He was widowed by then. You may be looking for his "grandson"?
if most certainly he migrated to Kerr County with the Hardin families.
It has been a while since I posted to these boards. It was many years before I joined Ancestry. com as a member.