Around 1935-1936, Law started calling his Greys Law greys. Prior to that he called then Canadian greys in published fight club reports. This was his way of referencing they were Hanky Dean greys being bred in Canada for Col. John Madigan. They came yellow and white legged. All were straightcombed. They were the exact same blood as the Red Madigin Clarets. When he started calling them Law Greys he had infused O'Connel Albany(hen side) under a Madigan Grey cock. The yellow leg becoming more common with a white leg still expected. A later infusion of McNerney Greys solidified the predominance of yellow legs over the white. Law crossed these on a lot of his other good fowl and advertised and sold a lot of fowl. A successful cross was the Law greys to Madigan's Texas Ranger's. These came dark legged. Therefore, if you have dark legged Law Greys and the trait is due to Law's breeding and not some other breeder afterward, then I would guess it is Ranger blood.
From my research, during the era of the Lawridge Plantation never was there a pea comb Law Grey shown. However, there is evidence that some Boston Roundhead was bred into some matings.
As ol Paul Harvey would say "Now you know the rest of the story.”