The Vtg Stencil font series by astype is based on real world stencils. The US No. 51 design was derived from authentic stencil plates used by the U.S. Army in the 1950’s and 1960’s. If you are interested in the current stencil design please have a look to Vtg Stencil US No. 72.
Font Family: Vtg Stencil US No.51 Regular