I've never seen or heard anything that would indicate Robeson ever made a rooster comb.
However, I used to think that about the swell-center, equal-end surveyor pattern moose, too. As of this writing, I've now seen two. The first one I ever saw was an essentially mint appearing salesman sample with brown bone handles and a dollar sign within a circle with wings on either side as a shield. Those of us that examined the knife were pretty sure it wasn't original. We thought one of the blades was a replacement. It probably was, but it was a beautiful knife, at least four inches in length. The second one was a well used example on Ebay.
So, maybe there's a farmer's jack/rooster comb out there somewhere. Robeson was certainly in the business at the right time to have made the pattern.
DE OPPRESSO LIBER
"...Men may spurn our appeals, reject our message, oppose our arguments, despise our persons ___but they are helpless against our prayers. "