Smokin' Gun; I am not lucky, or wealthy enough to one more than one original Colt, an 1896 vintage SAA in 38 WCF (refinished and well used)
As no one else chipped in, I dug out my Cartridges of the World, 3d Ed. and McDowell's book which was a present from my kids a few years back. Very interesting book. I yield to your actual possession of the piece and you can say if a 38 S&W fits. I was speculating based on McDowell, that Colt likely made these revolvers in either 38 Short rf, or later in 38 SHORT Colt cf. What happens after sale to a customer is beyond anyone's control. I will give a few cartridge dimensions for you to chew over;
38 S&W; bullet .359 neck .386 base .386 rim .423 case l. .78 oal 1.20
.38SC/.380 revolver; .375 .377 .380 .426 .70 1.10 (Colt based their round on the Brit. .380 rev.)
.38 short rf; .375 .376 .376 .436 .768 1.185
Note that 38 S&W is inside lubed with a .359 bullet. The other two take .375 heeled bullets, and both are slightly shorter than the .38 S&W.
You make the call. I'm only reading a book.
P.P.S; I still LUV the grips!