.38 S&W and .38 Colt are essentially the same round - S&W is a round nosed bullet, Colt is flat.
It is not .38 Special! Your gun is designed for a .361" bullet so, safety precautions aside, accuracy would be less than optimal.
EDIT: OK, it turns out that my reading comprehension skills are pretty terrible. I guess that if it says .38 S&W SPEC, that means .38 Special. But if it chambers a .38 Colt, I would say that my comment about accuracy holds.
You could always slug the barrel, then you'll know for sure.
Well we don't rent pigs and I figure it's better to say it right out front because a man that does like to rent pigs is... he's hard to stop - Gus McCrae