Cajun Accordion - John Mrnustik Tags -Unknow maker

This looks like a "Master" brand Cajun accordions were handcrafted by the late artisan Charlie Ortego in St. Charles, Louisiana. Ortego was widely recognized as a premier craftsman who built custom, highly sought-after diatonic accordions prized by traditional Cajun musicians for their distinct tone and craftsmanship. Found on this one is a tag from "John J Mrnustik on it. I was also told this is a Shine Mouton Cajun accordion,left-handed customization model. I know nothing about this but information below is on tags on this item.During his repairs, he'd make pieces of the accordion from scratch, sometimes stamping his name or a symbol on the replaced part.  Rumor has it that he actually made completed accordions in his lifetime.  According to his widow's conversations with accordion builder Larry Miller:
He would only make them when he had an order for five or more, and he sold them locally and to Cajuns in Southwest Louisiana. His widow told Mr. Miller that he made "over ten accordions." However, most believe he only made repairs.   His grand-daughter, Glenna, confirms this as well.
He had a shop in his store.  No, I don't remember him making accordions.   I only remember him making repairs.  I remember many of the polka and Spanish people coming to his shop.