[perezfan]

I agree that the auto is authentic, but the stem on the "T" looks to be re-traced. That particular ink is far thicker and bolder than the remainder of the signature.

Also, you can see what appears to be the original base of the "T" just to the left of the bolder/darker stem. The more faint line to the left looks to be the original stem of the "T".

Now whether it was Cobb or someone else who traced it over is anyone's guess. But most importantly, there should definitely be a disclaimer in the description which brings this obvious anomaly to light.