‘
Not sure when it started/stopped but Plate #’s in For Sale Ads was a CA requirement.
As you can see w/ both Wilson bros ‘Vettes, searching old CA vehicles today works well but 4x things required for success; #1- you need to know the Plate of course, #2- the vehicle needs to have actually been advertised back in the day, #3- the Newspaper page w/ Ad needs to have been scanned in recent years by the Newspaper groups which only a tiny amount of a percentage of papers have been, #4- you have to find the old Ad searching which usually involves sifting through tons of non-relevant results.
Got any old CA Plates you want to try Tim?

~ Pete
,