Help Identify Banjo!!

[beesbhive]

I purchased this at an estate sale for $150.00 is it worth it? Thank you The name plates or stickers are missing.  Looks old, is pretty heavy about 7lbs. Has 20 frets?? silver things around it.  Neck is 27" long, has five strings one missing on the lower knob,  Knobs look like ivory or bakelite.  Any info appreciated.