I had thought he was Frederick's (of Copiah) also but haven't seen a will for proof yet. Please keep me in mind if you run across a will for this Frederick. The 1850 census for my Samuel and family listed his wife Emily, Frances,(prob a daughter from a previous marriage) and other children Joseph, Isham(Isom), Penny (Pernia) and Presley (Priscilla). Later on they had Sarah David, and Melvina. The Samuel in the 1841 Copiah Co. Census was our Samuel. It's fascinating that your Frederick had a son named Samuel T. Hilburn also. It's also interesting that Vaughn Hilburn was in Hinds Co. MS. There is a marriage in Hinds Co. for a Samuel Hilbern and Elizabeth Hilbern. I have thought this might be my Samuel and she was the mother of Frances in the 1850 census.
Jerri