I have 45+ years in customer service management - in every instance where we made a misrepresentation to a customer, we made some attempt to correct it. If we could not correct it after the fact, then we made some other accommodation - if for no other reason that that is how we would want to be treated. Whether it is giving the customer some product (which only cost us about half the retail value) or providing some added service, it's an important acknowledgement of the customer and their importance. Making a mistake like this and just shrugging it off because it doesn't appear to make a big difference is poor customer relations, imo. I personally would not go back to that shop. If you're promised one thing but get another, it doesn't create confidence if they don't handle it well.