I have both volumes of Bernd's books also been chatting with him over the years as well by letter. you might be interested to know that the artist Richard G. co authored the two volumes on JG 300 with friend J.Y. Lorant. I've corresponded with both over the years as well, take if from me the lettering is in red not yellow-gold and is mentioned as such in the text of the second volume with several pics of Klaus and his red 1. Incidently the undercowling is not red either, much time has passed and with more recent photos the understanding of the markings has been explained much better for red 1 and other colourful JG 300 crates.