Lincoln was a pragmatist, he said what was needed depending on his audience and needs. I don't say he had no great accomplishments, but he was not nearly as progressive as many of his time.

His statement about how "free" those men were was wishful at best. Immediately after the Civil War came the Black Codes and then Jim Crow. The equivalent of slavery for many existed for decades after the Civil War.

That Lincoln may have evolved is certainly possible. I don't see the evidence of that, a speech from a politician is after all, just a speech from a politician.