Hi Lyndon,
I'm not sure on the early ones, a couple of blokes here really know the ins and out of them, but I think the red one was the first model. As far as I remember the second model was yellow as were all the later models. What you have there appears in excellent condition with all the bits needed for a complete restoration. One member here gml had a red and yellow pair that were just mouthwatering to look at. Been a bit quiet here on the Greenfield front over the last few months