I agree. Unless the vial received can be linked securely to the batch Certificate of Authenticity then its quality can't be assured. I haven't seen such a method in use by peptide sources. Even products from substantial compounding pharmacies I've used do not do this.Supplier "COAs" are mostly useless. Honestly I don't understand why people even bother asking for them.
Some suppliers like QSC, the former XCE/CA and a couple of others who I can't think of ATM will send samples to Jano for testing, and those do have a higher level of trust, but the reality is that unless you do your own testing or join in on crowdfunded testing you really can't know.