Couldn't help myself on this subject so I pulled out the Orange Parts book circa Nov 1975.
It appears that the original hood grilles were Matt Chrome, part number 51 13 1 810 539/540 and NLA. It then lists a new part number, 51 13 1 827 281/282 which is available today and is Bright Chrome. Chrome grilles were used "only for all dark paint coatings matt chrome up to chassis # 2240644 and 2250503." These are US VINs but euro VINs are listed too.
It also shows that part number 51 13 1 827 275/276 are "painted black for all remaining bright colors" after the two VINs listed above.
The reference to dark and bright paint coatings confuses things a bit but the real answer is that chrome grilles were used up to mid 73 US models then BMW switched to black grilles on all coupes. These US VINs relate to Feb 1973 build dates from a listing I maintain. This is what Carl and Peter referred too, the change was made in the middle of the US 73 model year. It also makes sense that all 2800CS coupes had chrome grilles. This is also the same month BMW switched to the larger electric window motors.
And 2250503 is in our Registry here in CA and it is supposedly original and is also coincidently painted Schwarz.
I recognize that this makes little difference to most members here but I find the the trivia related to our coupes interesting and sometimes even fascinating. I am sure Arde will have fun with this post!
It appears that the original hood grilles were Matt Chrome, part number 51 13 1 810 539/540 and NLA. It then lists a new part number, 51 13 1 827 281/282 which is available today and is Bright Chrome. Chrome grilles were used "only for all dark paint coatings matt chrome up to chassis # 2240644 and 2250503." These are US VINs but euro VINs are listed too.
It also shows that part number 51 13 1 827 275/276 are "painted black for all remaining bright colors" after the two VINs listed above.
The reference to dark and bright paint coatings confuses things a bit but the real answer is that chrome grilles were used up to mid 73 US models then BMW switched to black grilles on all coupes. These US VINs relate to Feb 1973 build dates from a listing I maintain. This is what Carl and Peter referred too, the change was made in the middle of the US 73 model year. It also makes sense that all 2800CS coupes had chrome grilles. This is also the same month BMW switched to the larger electric window motors.
And 2250503 is in our Registry here in CA and it is supposedly original and is also coincidently painted Schwarz.
I recognize that this makes little difference to most members here but I find the the trivia related to our coupes interesting and sometimes even fascinating. I am sure Arde will have fun with this post!