Schwimmwagen (Pics Added)

Hello, I am currently working on a Tamiya 166 Schwimmwagen. It's a really nice model. I am also using the Verlinden set for it and it is also excellent. My question is in regards to the Notek light. I have read through several reference books and looked online, but can't seem to see if the Notek was factory installed or field installed. The photos I have show a 50/50 balance and would like you guys input. Also, I am about to the point of paint and am torn between grey and yellow. Unfortunately, my reference photos are all in black and white and I can't decern between the two colors. What do you guys think? What color should I go with. I will probably prime either tonight or in the morning. I have a brand new bottle of Tamiya paint in both base colors. I even have a fresh batch of grey oils that I mixed up for my Stug (Which is sitting waiting to cure up). I plan on putting it in a waterside vignette with 2 figures. one seated and one getting the prop prepared to drop in the water. While I am on this subject, should I remove the back seats? the Verlinden set gives an option for this, but I don't know what circumstances that this would have taken place. Sorry for all the questions, but one has got to learn sometime.