You can measure the box and compare to the size of the batteries.
In this thread, Who installed 4 GC2 Batteries in their 36CKTS?
the 36CKTS was not originally built with a residential refrigerator and the battery box was not big enough for 4 GC2 batteries.
The pictures I have seen, the GC2 batteries in a 36CKTS sit side by side, right to left, 4 in a row.
I measured the battery compartment on a 2015 36CKTS with a residential refrigerator. It was about ~28-3/4" W x ~11" D .