That's a beauty! Same version as mine described and shown in post #65 above 3rd down on the left: Post war Trans. improved: rd gd, coil spring (this version has the same features as the early rd sight Baby J).
Some of the details from my commentary linked in post #82 above:
http://smith-wessonforum.com/blog.php?b=103
"1. TRANSITIONAL I FRAMES c. 1946, leaf main spring w/strain screw on forestrap: several pre war parts and stocks are used. These are "5 screw" models, 6 screws in total counting the strain screw: round sight, small trigger guard and short rd grip frame or rebated frame w/sq butt stocks, (all reportedly have new style hammer block).
---- a) Pre war/post war: uses many pre war parts mixed with post war parts. Earliest Transitional models with more rounded top strap built on a pre war frame left over after the war. Transitional models can also be found with the newly made post war squared off top strap as well!
(includes the non-Model #’d 1957 issue 196 .32 Regulation Police Targets with leaf springs in the low #657XXX range).
.22/32s shipped as late as 1953, as many as 30 units produced in the pre war serial range 534533 – 534557, completed/updated from pre war inventory; post war production begins at 534587 and continues through 534636 building another 50 units.
.32s beginning as low as 521XXX (Two in this range recorded as shipped in 1948 and 9/49, may not have the improved style rebound slide operated hammer block reportedly begun at # 536,685; #537670 has it), up to #550740 highest # known.
.38/32 S&W beginning c. 1948 at # 54475; as high as 582XX w/rd top stocks and 6 screws.
---- b) Pure Post War "Improved” I Frames w/coil main spring: "5 screw" model, (6th screw, the strain screw, was eliminated), late issues, lowest observed # have ramp front sight and barrel rib. These are not pre models.
No .22/32s made in this model, they used a target frame and are so rare, they went straight from the post war "Transitional I frame" w/leaf spring to the Model of 1953 New I frame;
.32s (beginning at #554536, lowest # known shipped 12/51, #56362X has rd sight, #611398 highest known; lowest known ramp sight w/rib #60430X, c. 1953);
.38/32s (highest round sight 70XXX [#68,XXX 2/53], lowest known ramp sight 70131, 71983 shipped Jan. 12, 1954, highest known 738XX)......."