What did GPA work at? IIRC, there were California Olive associated growers. They often bought wellused but, safely functioning weapons and issued them to guards. The guards were mostly anti-union, anti-immigrant and enforcers of the association rules and regulations. The revolver was probably a company/association issued weapon. Any idea as to when GPA came into ownership? The four notches are likely to be genuine. Four people may have been gunned down by the guard who was doing his job. OTT, it seems to be a NRA Fine condition Colt Single Action Army. If it has provenance, you could have a $4-5,000.00 revolver. Do all of the S/Ns match? I suggest a formal appraisal. Do you have any papers, news articles, journals or any written history to go with this SAA? Any oral history could possibly be confirmed. That is a great heirloom!!