BernardMarx:
I would have thought it unlikely they would continue to renew or be allowed to renew any patents/copyrights.
Patents cannot be renewed. The look of a product is not subject to copyright.
Does anyone have any advice on how to find out whether they would have a claim against me if I wholesale copied the look of this old product?
"Wholesale" implies you plan to make an exact copy which means you will run afoul of any trademarks.