Earlier or not, I think there's good evidence that West Africans came up with iron smelting on their own.

Iron artifacts in WF appear earlier than in North or East Africa, which means they had figured out ironworking before the technology diffused to their neighbors from the Near East. Researchers have also noted that their processes and furnace design are quite different.

West African smiths also seemed unaware of the process of quench hardening until much later, despite having "steel" (iron with high enough carbon content to harden through quenching). Even up to the 19th century, many tribal smiths in West Africa were observed hardening the edges of iron/steel blades and tools by work hardening instead of quenching. In contrast, quenching and tempering techniques were widely used in the East Mediterranean by at least 800 BCE, and knowledge of the process seemed to have spread alongside general iron smelting when it diffused to other regions of Europe/Asia. Hence, the lack of quench hardening among the West African iron-working tradition is good evidence that iron smelting technology may not have diffused to them (at least not from the Near East), but independently developed.