I suspect Glenn is correct, that it was probably built by Walter ("Shine") Mouton, who was from and built accordions in Crowley. Several years ago his nephew, Greg, began helping his uncle build accordions. Greg continues the "Mouton" name in accordions since Shine's death, building and repairing boxes in his own music store a few miles north of Crowley on Highway 13 headed toward Eunice.
While I was in Crowley in June visiting my family, I stopped in at Greg's store. He took considerable time from his work bench to chat and show me his current building and repair projects -- interesting seeing some old German melodeons he was repairing -- great Cajun hospitality!