This is not a behavior that every POS will want. So for me it must be implemented in a separate module.
Why is it 1? How about product with a UoM that is not in Units category.
What about barcode which include the quantity?
For me using barcode should be more strict than guessing with record name.
The POS should be configured to accept only specific code. The input should be validated before being used to search the exact matching product.
I think if the search has more than one result, there should be an error message.
Also the POS should support scanning gift card (and in the future promotion coupon).