Steve, I actually think your beautiful piece helps validate the OP’s autograph.
Looking closely, the imaginary baseline between “BB” and “King” lines up well; the second “B” sits slightly lower in both examples. The downstroke on the “K” angles inward just a bit, the “I” has a rounded form, and the second half of the “n” flows naturally into the “g.” The spacing and letter proportions are also consistent and exactly what I’d expect to see.