The main reason i made the plugin L4D2 only is that i didn't test if it works fine for L4D1 too. Besides that it's checking for some weapon entities that don't exist in L4D1 (which isn't much of a problem), it should work though i think.
If you wanna try it in L4D1, i'll make a version of it with the L4D2 check disabled for you (in case you didn't do it yourself already
). And if you can confirm me that it works without problems for L4D1 too, i'll remove the L4D2 only check.