I'm not sure which glow you mean.
To get rid of the shininess (blinking in the dark) do this:
Select NiTexturingProperty. In block details look for 'Apply Mode'. Change it from 'APPLY_HILIGHT' to 'APPLY_MODULATE'. Then double-click on 'EnvMap2' (name of NiMaterialProperty). Change the name to 'default'.
To get rid of any possible glow effects on the weapon do this:
Right-click on NiMaterialProperty. Select 'material' from the list. Set the emissive color (bottom right) to black (move the marker in the triangle so it points to black, which should be in the left bottom of the triangle).
Just remove both if you're unsure what to do and add it back later if you feel something is missing.