I played it back when it first came up on CL
Very sweet sound. The valves are very small like a euph or baritone.
The horn is from the 30s and is LOW pitch like A 435. From my first research i think it is a medium Eb Buescher, I recall they made 3 sizes, small, med, large. Original MP small 1" x 1"across and deep. It would clean up nicely. The horn is not leaky or worn. Maybe a little, tiny little bit more bass quality than my small Pan American Eb but not as much bass as my Conn New Wonder Giant Eb.
Joe Hunter