Generalisation in class diagram

I am modelling a sales system for a bike shop.

I have 2 classes that i need to discuss in particular - “order” and “invoice”

The order is the internal document used by the firm but the invoice includes other attributes from the “customer” class such as name, address etc.

As the two classes share values such as total, product number, part number etc, is having a generalisation where order ----> part a good idea?

Or is generalisation of only one class attached to a superclass a big no-no ?