Hi Mike, this is a customized version of the Spacerite Modified Roman alphabet with the serifs removed by the stencil cutter, typically called Modified Roman Sans. It became somewhat popular in the 1960s and 70s, though I’ve seen examples much earlier. It was popularized by many of the designers of the day, including Edward R. Peterson, and can regularly be seen in the design prints he sold to shops all over the country during that era.
Exactly where the serifs are were removed was up to the stencil cutter, so different shops developed their own styles especially on the curved letters, so there are often “semi-sans” versions as well.
The MLC has two available, a sans, and a semi-sans version, with some alternates for characters like ‘R’ that were often modified more significantly. The alternate characters are available in software that supports OpenType features, such as Adobe Illustrator and CorelDRAW.