If the welder knows their stuff they can lay the bead down in such a way and with the right penetration to form a pretty nice looking bead in the first place and in a way that will allow for some profiling. But if the bead isn't done that way from the outset then you're best off to leave it alone.
My old school R series touring Canondale has huge filleted beads. But since mine is the lower range "cheapie" of the series my frame didn't get the nice profiling done to it. So my welds look as if they were done with a caulking gun.