Where is the GECK reference to an iron sight's texture file?

[RokHere]

Hi. Can someone please teach me where or how to find the reference in GECK (or even FNVEdit) to the textures of a weapon's iron sights?

For example, for a weapon like the Cowboy Repeater, I can see that among the textures, there are these two files:

 

cowboyrepeatertangsights.dds

cowboyrepeatertangsights_n.dds

 

And while I can find a couple of references, in the Texture Set "1stPersonCowboyRepeaterTexture", like:

 

weapons\2handrifle\1stpersonCowboyRepeater.dds

weapons\2handrifle\1stpersonCowboyRepeater_n.dds

 

I cannot find any references to cowboyrepeatertangsights.dds. So how does the ESP file determine which iron-sight textures to use for the Cowboy Repeater, or any weapon for that matter?