
Quoting
Mr. Knowitall
It sounds like you have created a weak paper trail for yourself, so if he takes you to court you'll have to present your version of events and see which version the court finds more credible.
When you say, "both the seat and curtain airbags were not replaced ", I know what the curtain airbags are, but there's an ambiguity to "the seat". If the buyer agrees you made that statement and agrees that it was a reference to the passenger seat, your position will be stronger than if the buyer says he does not recall the statement or did not understand that you were referring to the passenger-side airbag.