Well yes, as I said, “will appear on the Odin mode / Download mode screen”.
No utility is required ! As you imply we do not know how thorough the supplier’s return process might be, but any (experienced) reseller would know that it is prudent to check the Download mode screen on a Samsung before sending a refund, I would think !
But of course you could offer to buy it on condition you experienced no echo on a custom ROM.