I have an old Masquelier catalog, and the late Don Zutz did an article on them for Shotgun Sports magazine, which is included in a collection of his columns called "Grand Old Shotguns". Masquelier made everything from very basic to very fancy guns.
Yours looks like a Model 120. My catalog has a decent photo of the gun and a description, but does not list a price--not that it would necessarily help because the catalog's not dated and we'd likely have to do a currency conversion. Yours appears to be in excellent condition.
Can anyone else read the date code? That's a good photo, but I don't see anything in my date code list that looks much like what I see in the photo.