ULTRA RARE Colt 1855 NAvy,4 screw frame,cut for shoulderstock with IRON BACKSTRAP

TRA RARE  Colt 1855 NAvy,4 screw frame,cut for shoulderstock with IRON BACKSTRAP, Flayderman P 89/90, item 5B 060

Colt 1851 and 1861 Navies book by Jordan and don Geri, page 93, stating that only 550 were ever made in the configuration for shoulderstock 4 scew and iron backstrap.  Cut for third type of shoulderstock.  Truly the rarest variation of a navy colt to be found.  Most were sold to the civilian market and thus had silvered brass and a varnished stock. 

serialnumber 163693, all  matching, except the wedge, has no number.  the bore has good rifling but also some markkings, but try to find another one of these. 
Grips are original, the right one is missing a sliver, overall 95 % orig. vanrish. 90 % silver on brass.  
Scene is 100 %, barrel has 20 % orig. blue, frame 35 % casehardening, lever 50 %. very sharp exterior, no loss of metal, sharp angles, works perfect. Truly a super rare find.  BEST OF BEST