Hello again, The coat you have shown does indeed look like Mink fur. If it just needs a small amount of basic stitching at a lining seam and has no other damage it looks like a nice coat. We're unable to discuss value here though. Sorry about that. Let me show you a few examples of some 50s fur coats though so you can possibly see some of the differences.
This photo shows some faux furs from 1957.
Notice the features of the striped fur. Rounded collar,
wide turned back cuffs, squared shoulders,
shorter sleeves, fitted top flaring out to a swing
style at the bottom.
Next is a Mink coat from 1953. No shoulder
seams, shorter sleeves, wide turn back cuffs,
fitted top, flared out swing style bottom.
Next; 1950s wool and Lynx fur jacket with silk satin lining.
If your coat was from the 1950s I would expect to see a more defined collar, shorter sleeves that were either fitted or had wide cuffs, a more fitted body style on top with a large swing style bottom, and a silk satin lining.
Going into the 60s sleeves were still short, they even got shorter, then in the 70s there were a lot of princess style and belted coats that were fitted at the waist, and then by the later 70s coats had straight sleeves that were longer with looser body styles throughout. That style went into the early 80s when furriers more commonly used Bemberg satin to line their coat which came from rayon yarn rather than natural silk satin.
The coat posted in your photos can date within a few years either way of 1980 somewhere between 1977-1982. That is when the style from what I see fits best. After 1982 coats featured big shoulder pads and elaborate styles that I don't see in the coat.