When Jim Bowie fought and died at the Alamo, the "Bowie knife" was already promoted, and no doubt there were numerous examples among the Alamo defenders, and Bowie himself owned quite a few.
That said, they were all different from one another and a Bowie is knife was just about any big knife so named, regardless of design. They should not have said "Bowie Knife." The term should have been "A big knife sort of like Jim Bowie's."
The original, genuine, very first Bowie knife seems to be identified. It is a large butcher type blade with three serrated-edge silver rivets. It looks VERY Mediterranean. Bernard Levine, the famed knife writer has seen it and takes it to be the original.
Whatever Bowie carried at the Alamo it seems NOT to have been the original. Keep in mind Mr. Bowie used many such knives and occasionally gave one away I am told.
The knife shown in the picture is the so called "Bart Moore Bowie" which was allegedly found at the Alamo by a Mexican soldier. It later came into the hands of the Moore family of Riverside, CA. It has an oak handle, and the blade was once longer, the tip broken off somehow and the blade re-shaped. The crossguard is designed for fighting and trapping an opposing blade. The blade shows skilled silversmithing in the fittings and is of hand-hammered carbon steel.
Was the Bart Moore Bowie made by Mr. Black? We do not know. The Moore family refused scientific testing so we cannot say if the story is real.
If you want one of these Bart Moore Bowies, send that picture to A.G. Russell. I think there is a maker, Steve Voorhis (?) who makes examples identical to this knife for $400.00 or so. I understand that knife maker markets through A.G. Russell.