You can contact the US Treasury at
Department of the Treasury
1500 Pennsylvania Avenue, NW
Washington, D.C. 20220

General Information: (202) 622-2000
Fax: (202) 622-6415

Ok for one your 1923 is going to look differant just because of the size these notes are mucher larger than todays size. If you can see small blue and red fibers in the paper most likely its not a fake. Those fibers come from only one kind of paper and only the us gov. can use it, the fibers come from cotton "jeans) lol its sounds funny but thats what give are money that smell and the durability.