Joe - From what little I have gleaned from Confederate unit's arms reports and ammo requests I might offer this opinion. The old common usage of "Musket" seems to have been applied to smoothbore arms with three barrel bands. The term "Rifle" seems to have been mostly used (especially pre-CW) with rifled arms of two bands.

Of course all of this got knocked for a loop when they started issuing rifled three banders as a standard infantry weapon with the model 1855. Hence the odd term "Rifle Musket".

As others have indicated, there were a number of .58/.577 caliber models that could be "minie muskets" Out of the hodgepodge of salvaged, captured, new-made, or imported guns the Confederates could have used - I have found that distinctions were not always made beyond caliber and length.
If you had a company with 30 Long Enfields and 54 1855's and the balance Mississippi purchased Whitney's. They would all be three banded Rifled Muskets and 58 caliber as their only real points of uniformity. But, that would usually be enough - just having uniformity in ammo supply.

The term Minie Musket would be descriptive enough for a supply officer. Minie bullets with the powder charge for a long barreled musket, is what they would need to know.