I see that the Elgin grade 479 has a detent type stem. My question is this. Will a 479 movement set and wind if put into a case that has the sleeve type stem that is not held into the movement by a detent? For example, a case made for a grade 345. Will the movement work properly with a non detent type stem?

No, it won't.
Mike

If you are swapping out cases because one is worn or damaged it might work. You would have to remove the sleeve in the new case and use the stem that was in the worn case.
The problem is if the watch came in that type of case, is the other case appropriate for that watch. Will you be making an impossible combination? I guess if you want a carry watch it would be ok.
Also most of the small watches that I have tried to do this with are odd sizes. So the movement may not even fit in the case.