Texture Paths... Can't fine image paths to replace

[jabbamonkey]

I am trying to replace some textures for the stones/rocks (ex: RockLowA.png). I actually replaced the texture... but in the game,  SOME of the rocks were replaced (new texture), but others weren't (they used the old texture). I used letters a-f.

Textures\Things\Item\Chunk\ChunkStone\_RockLowA.png
Textures\Things\Item\Chunk\ChunkStone\_RockLowB.png
Textures\Things\Item\Chunk\ChunkStone\_RockLowC.png
Textures\Things\Item\Chunk\ChunkStone\_RockLowD.png
Textures\Things\Item\Chunk\ChunkStone\_RockLowE.png
Textures\Things\Item\Chunk\ChunkStone\_RockLowF.png

Note: The CORE ART says that these names should be "RockLowA" ... and not "_RockLowA" ... but "RockLowA" gives me an error message.

Let me know. Thanks!