Yep, read the link, Rat...sounds like one guy's opinion...but as to Smith deliberately nicking one groove to "identify" a particular revolver...I'd wonder just how they documented that barrel from the thousands that were made. Even in this enlightened age of computers, it would impossible from a practical viewpoint.
We've had three of the 637's here on our farm. Two went to my DIL and her mother, and the third is my wife's. All did well with cast bullets using WW alloy and keeping velocities down to standard .38 Spl speed. We use that load to duplicate +P 125 gr JHP recoil and get equal accuracy with it. Leading is not a problem.
Accuracy can be astonishing when all the stars are aligned. I once put 5 shots from a fairly new 637 into 1-1/2" at 35 yds...used a pair of Crimson Trace grips and the laser on my wife's 637 to do it by bracing my shooting strong hand against my hip bone...almost like shooting off bags it was so steady. In effect, it was 'shooting fromt the hip' but well braced as described above...that's one of the advantages of laser sights....the ability to use them in darkness and from unconventional positions.
For loads, try 4.5 gr of 231 and any good LSWC, I like Missouri Bullet Co.'s 158 LSWC and shot that super group using it. As always, this load is near top end of the standard pressure .38 Spl. loadings in Lyman's load manual. You should work up to it if you're interested.
Best Regards, Rod