White slings were mainly for parade issue and look really pretty, but if its the original sling thats still on there, I'd probably stay with that.
If you want to make it more of a collectors item, you can get all of the original accessories like the brass oil bottles, cleaning rods, brushes ect..
I have a no.1 MkIII .303 lee enfield with an original oiler, sling, cleaning kit, bandolier, and even a WWI dated canteen and helmet. I keep it as a display in my room. I love to see other enfield lovers drool at all of it when they see it.