You looking for refinishing or mechanical rebuilding to remove excess slack? The guy that built my Palma rifle used to tweak Redfield Internationals to remove slack. Mechanical repairs would be a different skill set than polishing and re-bluing. I'm not familiar with anyone that advertises the service but a competent full service gunsmith should be capable of doing either if they are willing. May not be cost effective considering hourly rates and you can get most models for less than $100 on ebay or other sites.
