Lever action variants

[47MolineRTU]

Anyone know differences between the older lever action rifles. From looking around the internet I have figured out first letter P is pistol grip and S is straight grip. Second letter c is carbine lenght barrel and r is rifle length. What does that a/b mean for the third letter? I have also noticed 472 has safety lever while 479 has push button. What are other differences?

 

[Aetheris]

The A or B lettering is the cartridge chamberings. A is 30-30 and B is .35 remington. As for other differences between the 472 and 479 I think it was just the safety.