3.3.1. Half-Rate Convolutional Codes
The specific mapping is not important. You can derive other mappings by permutating subsets in a way that preserves the main property of increased minimum distance among the subsets. However, you can create any other mapping, including symbol mappings for 8-PSK, 16-PSK and others.
If you create another mapping, you must correctly connect the branch metrics created outside the IP core to the input ports and correctly configure the polynomials GA and GB for the trellis generation.