Ok, after having enough time to sit and look more your MODEL #22121 setup should have a 5.57 ratio. I don't know what the G number is about maybe something for production? Any ways to verify the ratio take the 3rd member out and look at your gears, there will be numbers on the drive pinion and the ring gear. Here is another for anyone's curiousity.
The G number is apparently a production code for sure, whatever plant G is and the date 1883, so it could be the 18th day of the 1983 model year or it could be january 8th of 1983.
Yeah, we have been pretty crazy at work as well. Just let me know if you want me to ID your brake shoes (by picture). The rest of your parts will have to be gone through with parts books etc so hopefully you have a good parts person you can go to if you need to.