Hi there. I can say that these letters are in all likelihood a modern addition to the memorial, made to look vintage. This type of raised metal letter was not typical of these type of civic memorials of the time, which were almost always hand-carved in granite or marble–though the top of the memorial in this case is a ‘White Bronze’ metal memorial, which was very popular at the time and is actually Zinc. The material of the metal used for the letters would be helpful in dating them–but they appear to be aluminum or steel. Either way, you are looking at some sort of ‘slab-serif’ font to match it, or historically the terms ‘Full-Block’ or “Square Full-Block” were used in the sign-painting and memorial industries to describe the lettering you’re looking for.