Nice looking Double Bell.
The general shape is like my 1936 30I.
Agree it is a standard action.
The one pic showing a valve casing bottom does not match the 30I short action bottom.
Suspect it it may be a 60I.
The 30I is labeled 30I on the mouthpiece receiver.
Jim
Jim Babbitt
1960s 4 valve and 1971 3 valve Besson New Standards (Denis Wick 6BM) for regular playing
1936 Conn 5 valve 30I Double Bell (Bach 6-1/2AL) General Purpose Back -Up
1924 Buescher 5 valve (the Denis Wick is close) and 1940 Holton 5 valve (Bach 6-1/2AL) Double Bells for kicks.
1860s OTS Saxhorn when history is required (the Denis Wick fits)