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No, this one is assembled the only way possible.

The pigtail gives it away as pre-1919. The maker is Weidlich of Regensburg in Bavaria. That German state for reasons unknown to me had a tradition for putting the semitone in the first valve. I have a suspicion that it was only a smaller region adhering to that tradition, but I haven’t seen much, if any, writing on this subject.

Klaus

One of the horn lists had discussions about the sequence of valve intervals.

There was a strong advocating for the reason being, that the first valve ever was a whole step valve and the next one introduced was teh semitone. The third has had various intervals Most common is the minor third, but the major third was common in Denmark, Sweden, and France a century ago. the French even had it being and ascending major second on their piston horns (now obsolete in professional orchestras).

My own take is not related to music, but to production: It is so much easier to have the shortest loop assigned to the center valve in a cluster, pistons and rotors alike.

Klaus

Take any standard fingering chart, and simply swap #1 & #2.