38 Colt & 38 S&W are two different cartridges. Just like any 38 Spl. will work in a 357 Mag, any 38 colt will work in a fire arm chambered in 38 Spl. Remington makes both, and they run 25 to 30 dollars a box of 50 down here in Bryan, Tx.
Now with that said, your revolver may chamber the 38 S&W. The 38 S&W has a tapered case ( bigger at the base than the neck) where as the 38 Colt is a straight wall like the 38 Spl or 357 mag or max. If your revolver has a slightly larger chamber, then it should take the 38 S&W. My Ruger SP101 will load the 38 S&W but my S&W M60 and Ruger LCR will not.
I do the same thing. With new shooters, I will lay out different revolvers of different sizes and weights, along with different loads like the Remington 125 gr 38Colt, Winchester 130 gr 38 Spl, 130 gr +p, and 125 gr .357 mag. They will figure out the one that fits them best, then run them through the basics, then I'll start them with the lightest load (38 Colt) and work up from there. By the end of the day, they'll be able to make up their own mind about what they want to shoot or spend their money on..
The best thing to do, is give them options. Just because I prefer to shoot 180 gr 357 mags out of a 4 inch GP100 doesn't mean everyone will want a heavy revolver and full power heavy loads.