The part code prefix does not reflect the model code, on the AU the part code prefix was WR2A (sedan), WR2F (wagon) and WR5A (LWB), YR23 (Ute), for the EL the prefix was 96DA etc etc.
It is possible for a component to have AV as the siffix for the part, and this could be bumped to BA but the product code would then be AA#A_#####_AV
The only part code prefixes that reflect the Model are the spare part codes, but for the AU the prefix was "ER", but AU series 2 went to AU2.
I have got my feelers out and will endeavour to uncover the truth re the product designation