Just keep in mind that most relics here usually have hard a very hard time.
There weren't that many cars sold in the late 20's and most were converted to utes for farm use during the war years.
Most people here, like me, would have had absolutely no clue what a Robertson screw was.
Even less now.
So if they were pulling say, a dash off, they would not have had the right tool.
I've never seen a tool. So those screws would simply be an inconvenience and most likely thrown away.