Ruger will send you a free screw of the correct type. The sights you have are being used again on the New Model Flat top Blackhawks. Ask for a screw for one of those.
The collared cyl pin is no longer used on NM Super BHs since 2012. Earliest noted S/Ns of SAs with collarless base pins are as follows:
.357 Blackhawk: 38-18679, 2012
.41/.45 Blackhawk: 48-57763, 2012
.30 Blackhawk: 51-44885, 2012
Super Blackhawk: 87-96036, 2012 (87-81559 has a collar)
"Cyl pins just prior to this change had a different head design than the "old style" as well. The blue pins had four cut grooves and the stainless pins had 3 cut grooves." Chet15
Ruger continnually makes small changes:
From Kyle @ Ruger:
"Part of our "Lean Manufacturing" standards is finding new ways to produce firearms while reducing production costs. It's actually less expensive to use a stainless steel part and to apply a black oxide finish [some screws] than it is to produce an alloy steel part and to send it out to the blue department."
~2014 blued hammers and triggers changed to stainless on blued guns.
~ 2013 Redhawks switched to a firing pin bushing screwed in from the rear.
~ late 2015 Fired case no longer included with guns (began in 2000).
2012 Internal locks were phased out in on those models that had them (began in 2005).
2012 Earliest noted S/Ns of SAs with collarless base pins are as follows:
.357 Blackhawk: 38-18679, 2012
.41/.45 Blackhawk: 48-57763, 2012
.30 Blackhawk: 51-44885, 2012
Super Blackhawk: 87-96036, 2012 (87-81559 has a collar)
"Cyl pins just prior to this change had a different head design than the "old style" as well. The blue pins had four cut grooves and the stainless pins had 3 cut grooves." Chet15
2009 Steel ejector rod housings on SBHs and Bisleys. Blackhawks began transitioning to steel soon after.
2009 Rear sights changed to steel with bird cast into tang.
2009 CCH New Vaq eliminated.
2008 Blued cast steel rear sight body with Ruger bird cast into tang.
2007 Laminated wood grips (Altamont replace Letts when they closed) or black 'plastic'; solid walnut or solid wood of any kind phased out.
2006 Billboard message moved to the bottom of the barrel.
2004 to 2012 phased in smooth triggers instead of grooved on SBHs:
hammers, triggers and ejector housing attachment screws used on blue models are all stainless as their blued counterparts were eliminated. The screw is black phosphated (if worn shiny they will not take bluing.) Occasionally Ruger substituted SS parts when they were temporarily low on blued parts inventory. But it has become standard practice because these parts in blue can no longer be ordered, and are listed as discontinued. Stainless can be blued however, by those refinishers specializing in it.
~2000 Aluminum alloy grip frames have been powder coated instead of anodized for several years now.
~ 2000 Rear sight blade with hump began.
1999 steel replaced alloy ERHs on Vaqueros.
1996 to 1999 All frames rear surface and grip frame ears raised for universal fit of Bisley grip frames
1980s past 1983 studded barrel for ejection rod screw eliminated.
1985 pointed ejector rods phased in.
1978, Jan., Barrel warning began on the left side.
