This bowl is authentic and verified as Hempstead Engraved style from around 1200-1500 AD.  It belonged to Lionel Barrett, a member of the Volunteer State Archeological Society of Tennessee and member of G.I.R.S. (Genuine Indian Relic Society). He had been collecting for 45 years and the bowl was in his collection for about 10 years.  He purchased it at the home of Nashville collector Mickey Johnson from Sam Johnson, a collector and author located in Arkansas.  The piece is in excellent condition with fire cloud markings from the pit firing and the Hempstead cross-hatch / triangle design with the surface polished.  The Hempstead Engraved pieces are found in the Quachita and Red River area of Southcentral Arkansas.

Excellent reference sites:

Prehistoric Caddo Indian Pottery - Sam Johnson

The Making of Caddo Pottery

Louisiana Caddo Indians