OK, I own a 99 with a scope. Came that way to me. My dad had one w/o and almost cussed it every time he had to make a long shot. The factory sight distance is short. A Peep would lengthen the spread and help, but a good scope job would help more.
OK, so you have an original. They made about a million of them all told. It ain't like there aren't any out there. It could have been scoped by any member of your family at any time, but the decision finally rests with you, or your kids?
You don't sell guns so you don't care about value except as family heirlooms and shooters. Do your kids feel the same way? If so, forget the "value" crowd - they have a point, but it only applies if you sell. Do what your family wants. Ask you kids if they want it with, or without? If they vote for scoping (family consensus), do it.
However, I'd be
very careful about doing it. I'd find a gunsmith who I really trusted to do it right with the right tools including alignment guides. Once done, it can be mostly undone by removing the bases and filling the screw holes with blind/plug screws smooth with the surface. Once the holes are there, you can mount a receiver peep on the back holes and leave plug screws in the front base holes if you wish. You and your family will have maximum flexibility in any sight configuration. that will guarantee that it gets used for the longest time for what it was created for - hunting and shooting
Adding sight screw holes properly will take maybe $25 off the sale price of the rifle. Doing so badly will ruin the gun for any resale value, except as a shooter. It's worth the time and trouble to have someone do it right - just like it would have been done in the past - good workmanship pays