Some builders who have not yet mastered engraving will hire it out, including their signature. Potentially was built by Steve Flowers, and engraved, and name signed by another (Lester Smith perhaps). Especially if you see no other signatures on the underside of the barrel.
97% of builders who are signing a gun do so on the top flat, between the rear sight and tang, where this particular signature is. Once in a great while, the owners name is here (as in the case of a gift rifle), and the builder signs it on the bottom of the barrel, in the same area.