Looking at this site (
http://tonybrong.blogspot.com/2011/1...get-match.html), and the photo I have of the gun, it does look like a pre-war version given it has the figure 8 type of arrangement to hold the cylinder.
"Pre-war guns used a flanged screw and stud device to hold the cylinder in place. It’s a ‘figure 8’ arrangement on the right front frame. When the screw is backed out, the flange on the screw draws the cylinder retention stud up with it."