It will slide into a 31/32/33, but it won’t operate with the .357 rounds. That is a 22/23/27 .40 cal magazine interchange, not 9mm. The only way it functions in a .357 is if you have the pistol converted it to a 9mm. So technically no longer a 31/32/33 model.
Just a heads up. If you sell it to someone stating it works in a .357 Glock they might not be too happy when it doesn’t.
I think this discrepancy is why people are confused.