I’d give the OP the benefit of doubt. I’ve always read that rule as discouraging excessive self-promotion, not a ban on one-off ones, and I think that should apply even when that one-off happens to be the very first submission by the account in question.
I'm not saying that the account should be banned, or that self-promotion should never be allowed. Nonetheless, the account creation date and lack of other comments clearly shows that it was created for the purpose of selling the submitter's product. I think it's fair to flag this submission dead and then see what else the person does with their account, if anything.
