What were these plates used for?

I found these in a box of parts the other day but nobody can tell me what they were used for.

 

Registration tags during the war years, to save metal for the war effort.

 

I was told they didn't make reg. tags during the war years, but hell I dont know that to be fact

 

"hold my beer and watch this"

Really scary when you hear your pilot say this! DD

 

There's a picture of them on '42 base plates in the Jim Fox license plate book.

 

They may be year tags that were attached to the regular size plate
you already had. Saved metal by only making the small pieces.

They did that sort of thing in Missouri in 1949-50 and 51.