Thank You. That is what I saw in a prior issue. There are only 5 known on cover, all postmarked from Detroit. The dates of usage are between 5/20/1911 and 6/1/1911.
I have a used single with a Cincinnati, Ohio CDS dated 5/24/1911 and one on cover with a perforated control mark from Chalmers Motor Company, Detroit, dated 5/22/1911.
One used single with perforated control mark went through an auction and sold for around $1100 including premium. I'm surprised Scott didn't pick up on that and assign a value.
I'm considering listing this single on
ebay and am not sure where to start it.