Like what was said earlier in the post. There were about a dozen or so in the same area in Missouri and MM just gradually bought them all out over the years. I really don’t think they have much competition anymore.
OK, top is a 3/8" cap, drill the top out and dremel sanded. Second down is a 3/8" to 1/2" ferell. both are copper. Bottom is a brass compression ring from a 3/8" shutoff. They are a bit tarnished, but they are working