I used to be really into the .410 loading, and have had a few of the Mossbergs. There are no stocks specifically designed for the .410 receiver, as it is physically smaller in dimension than the 12- and 20-gauge receivers. I have fitted an aftermarket stock to one, but it wasn't a smoothly finished job.
Was it this?
Springfield Armory M6 Scout - Wikipedia, the free encyclopedia
If so, AFAIK they are really hard to find (might not even be produced anymore), and are quite expensive (like $600 or something).
I'd almost say your best bet might be a single-shot .410, or even a longer-barreled .410 revolver, if you want a .410.