Thought I'd do movie posters for a while. This is the original 1951 one-sheet as issued by National Screen Service (NSS), dimensions of standard one-sheets from this era are 27" x 41".
All the Alice movie paper its identified by is NSS code 51/408 - which means this was the 408th film that NSS recorded in 1951.
A lot of people mistake these numbers for the dreaded Limited Edition number that has become rampant in the contemporary world of 'collectibles'. But it has nothing to do with number printed, it is merely an identifier for NSS purposes.