No 8 BSA sight question

Hi: I picked up a BSA no 8 sight that has been in a fire. The adjusting knobs are something I haven't seen before. i would appreciate any information available inlcuding how to disassemble the knobs. The threads are interesting 40TPI the exterior of the sleeve is a left hand thread.Attachment 60526Attachment 60527

Just looking at it I'd say a flat screw driver and a pair of snap ring pliers. Somebody who knows for sure will be along....