I agree, they will come.
I don't know any cases when owner stocked any frogs or similar amphibians but after some time they simply were there.
If only you wish to stock some special amphibians that certainly won't come by themselves then you may have a try but it doesn't mean they will like your pond.
I believe that they are like anything else. If you have provided adequate cover, food, and a place for them to reproduce, and your water conditions are suitable they should be able to sustain a population.
This may not be the case, but to me it is worth the time and effort. I could buy 100 mud puppies and raise them in a smaller body of water, make a large brood tank, and then stock them in my pond when I have a few thousand large adults. If nothing else I could have an endless supply of them to use as trophy bass bait LOL.
