If you have a model you want to use as a misc_model (i.e. it’ll get compiled into the bsp as world geometry, as opposed to being loaded at run time like a misc_gamemodel), and you want to replace the shader it uses, you can add the following key to the misc_model:
“_remap” “oldshader;newshader”
We did this a couple of times for various reasons (the snow-covered sand bags on Railgun for example), which is why you won’t find certain model/skin combinations in the editing pack.
You can also do a wildcard remap using “" (ie “_remap” ";newshader”) to replace all the shaders in a model.
On a side note, you can get away with using remaps even for dynamic models if you attach them to a brush entity as a misc_model, by placing the misc_model as you would normally and then targetting it at the brush entity. It then gets compiled into the bsp as part of that entity’s geometry, complete with your remapped shader.
That way you can reduce your pk3 size a little by avoiding having to re-path the models in npherno and distribute them with your map under a different name.