Rear End Housing "Cover" details?
 

Wondering what is correct detailing on the housing 'cover'. I've seen pictures that show "actual ratio" and others that show some "undefined number". There also seems to be an 'X' or 'Check Mark' on some pictures I've seen in addition to the aforementioned number. These pictures also do not reflect consistancy between using yellow and white colors for the markings.

Talking about a 69 Velle SS 4.10 posi, Atlanta, Mar/69. Any input is appreciated.