Difference between GCK60-23BX and GCK60-30BB

[fishpick]

Exactly what the title says.
I have an older BX24. It’s got a 60” deck on it. Model rck60b23bx

I can’t find a GCK60-23BX for it and it sounds like the newer models all fit the older tractors but what’s the deal with the -30BB
Does this fit my mower?

 

[fishpick]

Got my answers for anyone else in the future:
GCK60-BX23 is designed to mount to the subframe that the backhose uses
GCK60-BX26 is designed to mount to the 3PT hitch arms you can install on these smaller tractors
GCK60-30BB is designed for bigger tractors in the B series

if there are otehr suffix versions - good for them - I don't know what they are for!