If you can find a good Collector Grade, that would be nice indeed. My 1917-dated rifle was a bit well-used, though it cleaned up real nice. I did refinish the stock (personal preference), but I wouldn't have done with a real collector grade rifle. My second rifle is a wire-wrapped Indian of post-war make - it is undergoing restoration now. I'm stripping the stock and returning it to it's original pre-wire-wrapped state. The Ugly Duckling will hopefully be a swan. Purists - don't get your panties in a knot - these rifles are mine, and aren't of "collectable quality" to begin with.
For your friend, it sounds like he needs a really good one. I'd steer clear of SOG or Century - they have strictly "shooter grade" at best. Try AIM Surplus or Empire Arms (Dennis Kroh's company, IIRC) - they have much nicer guns! Good companys too.
Joe, the peepsight on the No.4 MkI has a large "battle sight" peep when folded, for general use. Flipped up, there is a smaller aperture on an adjustable slider - this is more consistent and accurate. I saw a feller here who drilled&tapped one and installed a target aperture - a very good shooter.
You could go the other way though - D&T the small peep and install a larger "ghost ring aperture" - that would be better for your eyes, and still decent accuracy. Better for hunting too, if you wanted to try it. I took a No.4 Mk.I hunting once, but it was equipped with a scope. I easily out-shot my buddy's brand-new .30-06!
I haven't handled a Longbranch, but I've heard good things of them.
My shooting buddy has a No.4 Mk.I made by Savage, and marked US Property.
It's in excellent condition, and is a very good shooter. These rifles always command higher prices in our gunshows.