I do not have a link to a "REST API Standard" that dictates whether what you propose is acceptable or not. However, of the many REST APIs I've had to deal with, I have not seen one that used the accept header like you are proposing.
What happens if you later allow flags on GET /products to include different levels of details about the products? You would need different Accept header values (example application/vnd.company.products-details-v1.0+json vs application/vnd.company.products-min-v1.0+json)
I believe you are better off with just one Accept header value.