Delayed reports happen all the time and an honest dealer will tell prospective buyers:
1. that the dealer can only be responsible for the report AT THE TIME OF SALE.
2. that the Carfax is a strictly voluntary reporting form.
3. that the Carfax report is anecdotal in nature and can be misleading (right side and left side can be mistaken...vs driver's side/passenger side) and mis-reported...note that in New York the only comment will be "accident reported" to avoid such expectations of observational accuracy.
4. that nonetheless, it serves as a guide to inspecting/evaluating repairs prior to purchase, even for cars that have a "clean carfax"
5. that all used cars, regardless of the Carfax report, should be independently inspected prior to purchase.
Any dealer/seller that fails to disclose any of these facts, or prohibits an inspection prior to purchase should be avoided.
From my own Carfax experience the right/left side repair was incorrectly identified, AND the repair was missed by the mechanic. The doors still had factory stickers, but the passenger door skin was replaced, only discovered after purchase when I noted a hollow sound coming from the door upon closing, a "ping" rather than a thud, and was correctly identified by a body shop that installed a sound absorbing pad to the underside of the skin (restoring the thud) that had been neglected in the prior repair. The paint match was perfect though.