If you have compiled anything for Insurgency, you have most probably noticed the oh-so-lovely "sleeve bug", having US sleeves even with Insurgents.
Easy to fix but very annoying if you don't fix it.
$model "arms" "arms_marine.smd"
$model "arms" "arms_iraqi.smd"
in your QC.
Also it may not show up in HLMV, but it works ingame. This is why I spent a lot more time figuring it out than I should've ;D