I once had to explain it to a cop, but he'd been around long enuf to know what i was talking about.
On the other hand though, theres some kid cops that,,if the vin isnt in the corner of the windshield,they have your truck towed and the burden of proof is on you.
Plus getting jerked around for 3 or 4 days while you get it straightened out.
Then you just pray for someone at CHP that is familiar with these old ones.