Generally speaking, the older the revolver, the more value there is to the box and papers. However, in the example stated (19-3), I would say the original box and papers would only add $30-$50 to the overall value.
I think in most cases it adds only the value of the box. BUT if you notice on Ebay and GB the boxes listed only go up. Seems like a lot of folks will lay down serious bucks to box-up their revolvers, and that's what counts.
We're seeing a change of only gold boxes bringing big bucks. Here's one I paid 1/4 the price of a K-22 for. And was glad to get it.
I agree with Doc44 about the price. I also think the original box will make the gun more desirable, collectable, and sellable as time goes by. I try to only buy boxed guns, but I will admit that many unboxed guns have followed me home. Another solution: Buy both guns, safe queen the boxed gun and shot the unboxed gun. One can never have enough .357 K-frames! Good luck.