Accordions (even the hard cases they come in), like motor cars, men's and women's clothing and hairstyles, follow strong stylistic trends.
While not holding myself forth as an expert, my feeling would be that this instrument is likely from the latter 1940s.
Unfortunately, I'm unable to make out the designations on the couplers in the treble , which would indicate the number of reed banks.
Two couplers in the bass may signify as few as two sets of bass reeds.
Personally, I have a soft spot for instruments of this vintage.?