Yes, with the "they," you clearly need "are." However "as-is" is also an idiomatic use that means "in the condition they are in."
These items sold as-is, for example, means "they might be damaged, but that's what you're getting, so don't look for a discount because of it."
So idiomatically, you could say "Just leave them as-is." Don't bother fixing them, making them prett