Yup, first day of any Ruger revolver production. There were prototypes before 12/15/53 but no production guns.
These are the guns assembled that first day: 2, 5, 7, 8, 12, 16, 71, 83, 85, 93, 126, 138, 153, 163.
So it is 1 of 14.
Ruger famously didn't assemble guns in serial number sequence...