From the look of the sticker to the right of the Data Plate, I'm suspecting it is a middle 1970s or so car? Yes, the axle ratio should be on the tag. A better picture would help, though.
In general, the format template for the Data Plate is in the front of the 1970s Chrysler Parts Manual, in the INFO section in the front. A list of the option codes can be found in the Library section of the Dealer Order Guide at
www.hamtramck-historical.com (might have to manually input that address). Follow the prompts to get to your model year and such.
The bulk of online decoders are for the more popular B- and E-body cars. Although there are some cross-overs of option codes, some do not exist in