I can confirm the dating to 1958, but I have no explanation for the "Abilene" engraving. I would guess that it might have been something that happened after the horn's manufacture, perhaps to mark the location of the retailer that sold it.
David Bjornstad
1923 Conn New Wonder 86I, Bach 6 1/2 AL
2018 Wessex EP100 Dolce, Denis Wick 4ABL
2013 Jinbao JBEP-1111L, Denis Wick 4AM
2015 Jinbao JBBR-1240, Denis Wick clone mouthpiece of unknown designation
Cullman (AL) Community Band (Euph Section Leader)
Brass Band of Huntsville (2nd Bari)