Hello , novice here on my 3rd set which is the beloved 1:72 Avro Lancaster B.III and I have noticed on a couple of parts on the instructions that is no number to paint the part , is that a typo or just leave them not coloured ( painted ) . It just seems little daft to leave parts unpainted or is that the norm ? As I said I’m a 42 year man who found the love of model late in life and has only started so please be kind .