Brian, Welcome to the forum. The 050 G means original body colour is white. The “G” is for Glasurit, the paint supplier. The 040 G means the original top was black, also Glasurit. As for the first line of codes on the paint plate, 426 is for automatic transmission and power steering. 491 is for US version, 503 is for left hand outside mirror and 515 is for Becker AM/FM radio, US version.
All this information is in the Technical Manual, third tab from the left above. I suggest you become familiar with the Technical Manual which contains a world of information. There are some restricted sections which you can access by becoming a full member, a bargain at USD30.00.
Did you purchase the car or are you just looking? Keep us posted and again welcome to the forum.