If it's playing ok it looks like a good buy at the price.
The treble couplers suggest that it's three voice LMH.
The buying survival guide at Ike's accordions says
On any of these accordions, the reed sets in the treble can be low medium or high octave also referred to as, Bassoon, Clarinet and Piccolo sets of reeds. These are often referred to in specifications as L, M, and H, for Low Medium and High. An accordion with LMH treble would have one set of Bassoon, one of Clarinet, and one of Piccolo tuned an octave apart. A few accordions have what's referred to as a "half-octave" set which is a perfect fifth above the Clarinet set.
To get "musette tuning", or tremolo, you would need at least two sets in the same range, e.g., MM. So an accordion with LMH 3 sets of treble reeds could not be tuned "musette". This is not to be confused with "French Musette" tuning, which is a technical designation for a particular type of tremolo tuning requiring 3 sets in the same range, e.g., MMM.
Later on in the last half of the 1900's LMMH, LMH, and LM became more popular reed arrangements, than the MM, LMM, and LMMM, but then more players in the 1980's to present started demanding musette capability, so the LMH and LM reed configurations fell out of favor, and are now very rarely made.
Which suggests it's a bit later than 1940's, which I would have guessed from the look.
Tom
