Howdy!
I can't comment about a S&W 24 since I don't know what that is, but in the WB match I put on a few years back, your S&W 1917 (and the Brazilian contract edition) would have been perfectly welcome. As for "action"; revolvers with reloads with moon clips can be incredibly fast; just ask Jerry Miculek!
As for cutoff dates for WB firearms; I've seen it vary over the years depending on the club's house rules. I went a little later than 1914, as I wanted people to be able to bring out a variety of stuff. (Heck, even the movie plays a little loose with its gear time period; the machine gun is a 1917, the rifle of one of the posse members is from WW2, the clothing of the gang in the opening scenes has some WW1 or later stuff from what I've been told, etc.)
As for SASS's official renditon of a WB match; I can see why they chose to put such significant limitations on guns and gear, but I don't feel local clubs should or need to be so constrained.