I've thought long and hard about this so I went to the Westmont Il service center about 2 hours ago. As luck would have it.....There were 2 earlier model 3's there as well as mine.
Blue Model 3 - Full back Red colored glass in the rain.
White P3D+ ( mine ) - No Red look at all on the rear.
Black P3D demo driver car - Half Red colored glass in the rain.
Below is a pic of My car and the Blue one to the right.
View attachment 330152
I was vehemently presenting my case that I was missing some kind of UV coating or something. The service manager and I went back to the Tesla Parts computer and he looked up what rear window belonged on the back of my car. After searching and searching we found it. xx-A2 is the part number that showed up on the left (drivers side) of the rear window right above the C-pillar. Then we went back to my car and found the number and sure enough I have a xx-A2 window. I then went to the blue model 3 next to me and it was also xx-a2.
I was thinking.....what's going on here? Then after further research on the Tesla Service Computer we found that there are 4 different manufacturers of that rear window. The company that made my P3D+ window film that is sandwiched between to the 2 pieces of glass that comprise of the rear window is 3M. We were only able to look that up via the VIN.
Tesla had some kind of uv light meter and I was able to compare the uv light from my rear window and the blue cars rear window and the light meter showed the exact same numbers. We then took the light meter to a Model S CPO 2013 Model S rear window and the numbers of the meter were doubled ( more uv coming through). Interesting.
So.....the Customer service manager suggested to me that if I ever have to replace the rear glass in my Model 3 to remind the Tesla Service Center to replace the glass with the glass assigned to my VIN because the rear window part number is the same across all Model 3's.
Then the Customer manager asked me an ALL IMPORTANT QUESTION....that I could only answer after seeing all 3 cars together.
I have a White on White P3D+ FSD Model 3. He asked..."Out of all three versions of the rear window....with your white seats and all...….Which window would you have ordered?".
Without hesitation I responded "The one I have".
I said this because even when the rain stops( on the full red window as well as the half red window) ….the red of the red window blocks out the ability to see the color of the interior. I want to be able to see my white seats from the rear. Its beautiful.
Case closed for me.