Definitely knid of unusual button, doesn't look like a standard navy issue. Wings are in a relaxed and drooped position along with the anchor to the right. Wonder if it's a local issue?
The button appears to be NA 57 b,23 mm,RV 15,Navy 1-piece convex in Alberts book.It states that the back reads "Treble Gilt/orange" and has 16 stars on front.I believe is is from around 1802 era.