How To Disable Server Custom Models In CS 1.6

[Fisma10]

The Server I Sometimes Play On Changes The Hostage Models, But I Would Rather Use The Old Classic Models For Them. But If I Use "cl_allowdownload 0" It Doesn't Let Me Into The Server, And A Popup Appears Basically Saying I Need The Custom Model Files. So I Tried Replacing The New Model Files With The Classic Ones, But It Crashes If I Try Play It, Saying "Client World Model: Null". So If There Is Any Way Around This It Would Be Appreciated.