Most guns including Glock will be interchangeable between 357sig and 40sw, so long as the conversion barrel length matches the frame size (sub-comp/comp/standard). The mags are the same, so all you need is the conversion barrel.
If the price is right, have at it. If I had a Glock 22 or 23, I'd probably have a conversion barrel or two for it. They're available from Lone Wolf new for $100-125. 40sw Glocks can easily and affordably be converted to 357sig or 9mm. That's one trait I really like about Glock.
Some people prefer the 357sig to 40sw as a carry, home defense, or hunting BUG (due to increased velocity and flatter trajectory)...and you'll be able to shoot the cheaper 40sw at the range.
"The Future is Unwritten"