Thank you for all that research @Wulger! Yes, I have seen all these photos as well. And I read lots of documentation but yellow cowling was never mentioned. It just complicates the depiction of this aircraft. I did see some models like that though. I have read speculations about RLM 02 on the fuselage, 02/71 and even 70/71 color schemes but not seen any info on yellow or any other different color on cowling.
It seems like I just need to make a decision and go with it.