[kruador]

No, they aren't. GS1 - the organisation that administers retail barcodes - has rules about when to change the Global Trade Item Number for a product. The GTIN is what you probably mean by 'UPC' but GS1 now distinguishes between the abstract product number (the GTIN), and the concrete barcode symbology containing a 12-digit GTIN (UPC-A).

The Guiding Principles are:

* Is a consumer and/or trading partner expected to distinguish the changed or new product from previous/current products?

* Is there a regulatory/liability disclosure requirement to the consumer and/or trading partner?

* Is there a substantial impact to the supply chain (e.g., how the product is shipped, stored, received)?

- from https://www.gs1.org/1/gtinrules/en/guiding-principles