Go into the "cstrike\materials\models\weapons\v_models\posh.spice.glock" folder and find the "Glock.VMT" file.

Open the file up and it should read:

VertexLitGeneric
{
//Black Slide
//	"$baseTexture" "models\weapons\v_models\posh.spice.glock\Glock"
//	"$bumpmap" "models\weapons\v_models\posh.spice.glock\Glock_Norm"
//Silver Slide
	"$baseTexture" "models\weapons\v_models\posh.spice.glock\Silver"
	"$bumpmap" "models\weapons\v_models\posh.spice.glock\Silver_Norm"
}


Change this so it reads like this:


VertexLitGeneric
{
//Black Slide
	"$baseTexture" "models\weapons\v_models\posh.spice.glock\Glock"
	"$bumpmap" "models\weapons\v_models\posh.spice.glock\Glock_Norm"
//Silver Slide
//	"$baseTexture" "models\weapons\v_models\posh.spice.glock\Silver"
//	"$bumpmap" "models\weapons\v_models\posh.spice.glock\Silver_Norm"
}


After doing that, save it, and then when you go to play CS:S, the TMP will now have the Black Slide.