I'm wondering if someone can help me identify this Hohner. ... It has a long bar for the bellows release button (see photo 02 ).
Now I'm home, and have had time to look it up, I can see that the 8-bass version of these, shown in both the 1926 and 1929 editions of How to play a Hohner Accordion
, "No. 374. Genuine steel reed Hohner Accordion, Stradella Model. ... Frames, panels and keyboard in dark mahogany finish with decalcomania border in mosaic design. Stradella corners" is different in that it has Stradella-style hooks holding the ends and bellows together, unlike the one in question which is pinned.
However, Catalogue No. 700
(that I'd date to 1929-30) illustrates the exact same style as this one (in 8-bass) as No. 384/21/8, with "finest American Jacaranda wood casing with maple and ebony inlays. ... Stradella corners, fretwork cover and frames with imitation mother of pearl inlay." Whilst the 12-bass version (like you're asking about) is not illustrated, but listed as No. 385/21/12.
Also, some other models in the same catalogue show the same, or similar, gilt Hohner transfers with the twin anchors (trade mark), and the long bar-type wind key on models with 12 or more basses.