Supertone D W #515

Hello everyone , Thanks in advance for any help or information I might receive here. I bought a banjo at auction this weekend and have not been able to find another like it or even a mention of it. I am hoping maybe someone here can help. I have seen lots of the Supertone Dixie Wonder models and even a 514 but have not found any information about a # 515. it is like the 514 but it has the entire fret board in mother of pearl. it is totally cool looking, but not sure how it plays, it appears all original and complete. A letter was in the case from when the gentleman who owned it was seeking info back in 1972, the person who responded stated the banjo was made in the 1920's. and said it sold for around $8 at that time. so do I have a good rare banjo or a great rare banjo? Thanks again for any information !