How to get the old forge hammer smacking the anvil for Forge mod loader

You can't, unless there is a texture pack that does this, which I don't think there is. If you use a modpack, It has to load the mod before using it, but the mod wants to change the way the mod loader (which comes while loading the mods) looks, so a mod will not do this. And other than a mod or a texture pack, I don't think this can be achieved. Also, upon searching, I did not come across such a texture pack. I don't think this is possible.