Any repair history caps a tire at Grade C, disclosed. Below C there is no grade: unsafe tires are rejected and never listed; sound tires that miss the floor stay off the marketplace, unbadged.
Never-mounted tires are marked New, not a letter: grading measures wear and there is none. They still carry a photo of the tire and the same NHTSA recall screen. A recorded DOT date prints on the listing and the 10-year ceiling applies to it; no date means the shop did not record one, not that the tire is fresh.
"Safety" items reject the tire outright. "Disclosed" items cap it at Grade C and appear on the listing. "Automatic" is screened for the tech: brand, model, size and DOT build date against NHTSA's tire recall list, refreshed monthly.
Three tread depths, the inspection checklist, and photos of the tread face, the outer sidewall with its DOT code, and the whole tire. All of it renders on the listing, next to the price.
A matched set is graded once: the shop inspects every tire, measures and photographs one, and reports the lowest tread across the set. The listing says so, and advertises the grade that thinnest tire can hold. A grade says what was measured on the inspection date, nothing more.