This is what we found out from our contact at the Diageo Archive Department (Diageo is Johnnie Walker's parent company).
"Johnnie Walker striding man statuettes have come in all different shapes and sizes, and in different materials over the years. The earliest ones seem to have been wooden with a green base and not dis-similar to yours. They were then made of rubber and then metal. Please find attached a visual showing some of the designs used."