Persona 3/BTL.CVM/MODEL/PACK

The BTL.CVM file found in Persona 3 contains a PAC folder. Each PAC in the folder contains an RMD model of either a playable character or an enemy, bundled with ACX combat voice clips.

Party Members
Models ending with an A (for example, BC002A.PAC vs BC002.PAC) are used when a party member has an evolved Persona. If the member does not have their evolved Persona yet (or in the case of Koromaru/ Shinjiro, doesn't get one), they will use the model that does not end with an "A". Presumably stands for "Awoken". The only difference between the two are the voicelines contained in the ACX file.

Models ending with "F" are used in The Answer. The only differences are victory animations and voicelines in the ACX.