On my last visit to the CMP in Anniston, they had a box of loose sights. Most were Redfields but there were a few from Kimbers. I recall seeing a Kimber sight that had the attachment base broken off. You may want to call them and see if you could purchase a distressed sight for parts (provided they still have any left in stock).
Also for your consideration, I picked up two Redfield Palmas that were missing detent balls on elevation. I used my small Allen wrenches as gauges to estimate the diameter of the missing detent balls. With this info, I went to McMaster-Carr and found that they stock small ball bearings of the needed diameter. I had to order a package of 100 at ~$8, but they worked great.
Good luck