Product Number on Sales Records
Starting in version 9.0 online, the following entities have a read-only field called productnumber: Quote Product (quotedetail) Order Product (salesorderdetail) Invoice Product (invoicedetail) The field is a read-only copy of the Product ID (productnumber) field from the related Product. Interestingly the field is not available on Opportunity Product nor is it available in Dynamics On-Premises.