Question regarding brand and possibly era identification

[A.N.Other]

I acquired an old 4 valve Tenorhorn as an occasional "budget tool for a doubler" which has the sole engraving "Symphonic" - see pictures. I am interested in knowing the possible manufacturer as this is most probably a stencil made for export(?). My research up to now led to Boehm & Meinl. I appreciate further hints and information about the horn regarding manufacturer and possibly era. It's certainly a (wide) Tenorhorn (not Bariton) despite the 27cm bell, as the bore is ~14mm and it features a small Tenorhorn mouthpiece receiver.

Thomas