That is an excelsior NY from the 1950's made in the USA with a combination of Italian and American parts. If I am not mistaken (and my history is weak), it was in the 50's that they started to move production from Castelfidardo Italy to the USA. It *is* possible this one is all Italian, but more than likely it is a USA made model.
Right side:
4 sets of reeds tuned LMMH, dry tuned from the factory
41 keys just over 19" keyboard length
Of note, they had 4 "rocker" treble switches that gave it a total of 15 different registrations.
It of course also had a master pam switch.
Left side:
5 sets of reeds
140 bass
3 registrations.
It was right in the middle ground at around 21 pounds without straps. That makes it quite light for an accordion of these specs. In good condition, these are awesome to play.
It is considered a professional instrument. My parents were looking at this model for me before they bought my beloved Morino VI N.
It is impossible to tell value from a single pic, but I will say that I noticed that there were some strong discolouration on the top of the keyboard that suggest mold... an accordion's greatest enemy. Mold takes any accordion and in terms of value, turns it from hero to zero in an instant.