That wouldn't be necessary. I had a metal phone with a replaceable battery (Motorola SLVR L7). It was more common for a cellphone to be made of plastic in the replaceable battery days because most phones were still far more utilitarian and thought of for talking, text messages, email if you had a data plan and of course Snake.

Lightweight and small was popular before large screens and smart features came along. One exception was the push-to-talk phones geared towards construction workers. Those suckers were chunky.