No Steve...dodgy one that.
Must have the correct stamp from the correct guy at the airport (they have individual stamps), and yes, Mrs. MUST be with you, daft a rule as that is.
Anything else will be recognised as fake by a sharp-eyed immigration officer when you eventually leave the country.
I know people who thought they'd 'bought' a retrospective Balikbayon stamp, and then came unstuck with it.