Personally, I've not seen the need for it. This does not however, mean I am opposed to fire lapping a barrel. If you choose to do so, I would go with John Linebaugh's suggestion and swab some of the compund inside the forcing cone of the revolver and not coat the bullet. He has told me that coating the bullet does a wonderful job of spreading abrasive compund all inside the workings of the revolver.
I would recommend that if you have not shot your SBHH much; to go put at least a couple hundred rounds through it and see how it settles in before you firelap the barrel.