Jim - Is there a difference in cylinder length between those intended for 38 Colt and 38 Special?
Yes . . . if the 38 Spl. brass (or 357 brass) will work in the chamber, then I'm assuming that the bullet will have to be seated deeper in the casing . . . . and it's important to remember regardless of what case you are using, you'll have to stick to 38 Colt Long (or Short if you use Short brass) Data if the handgun is specifically chamber for 38 Colt Long . . . .
Hawg - You're certainly right on trimming the 38 Spl. back to 38 Colt Long. I load quite a bit of 38 Colt Short, Long and Special . . . enough of it that for me, I'm not going to spend time trimming brass when I can buy it. Plus, with what I load, I want the correct head stamp on it . . . but if a person is only going to load a few, then trimming is a good way to do it if they have the trimmer. I don't even own one and have never trimmed 38 Spl. or 357. . . . . usually in the range brass I use, IF there is a case length difference then it can be sorted by head stamp/length so you get a good roll crimp on it.