[Crazy Dazz]

I've a bit of experience dealing with vehicle auctions.

The auctioneers always appear as dodgy as **** because they are trying to avoid liability under your state's Motor Trade legislation.
Auctioneers ALWAYS try to claim that they are only ever acting on behalf of an actual vendor. If you buy a house at auction that's very clear, standard, and understood. Unless they deliberately misrepresent the house somehow, it is a contract between you and the people selling the house. If you find it's rotten with termites, or illegal wiring, or bodies under the patio, that's between you and the previous owner.

Your state's Motor Trade legislation will call BS on that, otherwise every dodgy caryard would be doing it.

It's the reason they charge a separate premium. Their claim is that at most they would be liable to refund that premium, and the actual sale is between you and the previous owner.
Also why they sell them unregistered. If the car is a repo, they don't want the registration to ever record them as owner, so they will deregister it in the old owners name, hold it unregistered, and require you to apply to register it in your own name. (This seems to vary a bit from state to state, but it always comes back to them trying to avoid their legal obligations.)

In WA for example, the RAC claims that Vehicle Auctioneers (who are and must be licensed dealers) are acting as dealers and are therefore statutorially liable. The Auctioneers claim they're not, and to date the government has been too lazy to care.

Your biggest concern should be the inspection protocols in your state. In WA they are not a regular thing, but relicensing a car (even one licensed interstate) requires an inspection. It's gotten a BIT better since it was privatised, but before (like all bureaucrats) they saw it as their civic duty to obstruct any attempt at relicensing.

As for the red plate. Well the VINs match, and it does appear to be affixed to a yellow car. Just make sure you save copies of those photos.
It's probable that the white section was a bespoke computer printed label affixed to a mass-produced plate.
It's also possible that the smartphone automatically applied OCR, and enhanced both the VIN and the barcode.

PS: Are you only interested because it's yellow?